Cerebral emboli and cognitive function after intramedullary fracture fixation

doi:10.1016/j.injury.2008.11.024

Injury

Volume 40, Issue 7, July 2009, Pages 742-745

https://doi.org/10.1016/j.injury.2008.11.024 Get rights and content

Abstract

Introduction

Cerebral emboli have been detected during intramedullary orthopaedic procedures. The quantity of emboli produced and their clinical effects are currently not known. This study aimed to quantify the intra-operative cerebral embolic load using transcranial Doppler ultrasound during the intramedullary stabilisation of femoral and tibial diaphyseal fractures. Clinical cognitive function was also assessed after surgery and any relationship to the cerebral embolic load determined.

Patients and methods

Prospective cohort study of 20 patients with femoral or tibial diaphyseal fractures treated with reamed intramedullary nailing. The intra-operative cerebral embolic load was measured using transcranial Doppler ultrasound of the middle meningeal artery. Cognitive function was assessed 3 days after surgery using a range of validated neuropsychological tests. The cognitive results were compared to predicted scores matched for age and intelligence quotient as is the standard method of cognitive assessment after trauma.

Results

Four patients had detectable cerebral emboli with counts of only 2, 3, 3, and 9 respectively. A significantly poorer than predicted cognitive score occurred in immediate and delayed memory recall tests. However there was no significant difference in any cognitive function score between those patients who had detectable cerebral emboli and those who did not.

Discussion

Small numbers of cerebral emboli were detected during intramedullary stabilisation of lower limb long bone fractures but with no apparent cognitive effect. This poor correlation is similar to recent studies performed on arthroplasty patients and also conforms to the extensive cardiac surgery literature which would indicate that such low levels of systemic embolisation are unlikely to consistently produce cerebral clinical effects.

Introduction

Concerns exist about orthopaedic procedures which instrument the intramedullary canal due to the production of emboli. Pulmonary embolisation detected by transoesophageal echocardiography during such procedures regularly produces detectable hypoxaemia and clinical effects.3, 15 In addition, cerebral embolic events have more recently been detected after intramedullary fracture stabilisation using transcranial Doppler ultrasound.⁷ Whether such events are associated with a clinical effect on cerebral function remains unclear. Sensitive and validated neuropsychological testing methods are available and have recently demonstrated subtle cognitive decline after knee arthroplasty surgery.¹⁶ However in this study no correlation was found with the detection of cerebral emboli. Cognitive dysfunction after cardiac bypass surgery is well recognised with a high intraoperative cerebral embolic load being a main predictor.²⁰

The aim of this study was firstly to use transcranial Doppler ultrasound to measure the frequency and distribution of intraoperative cerebral emboli during the intramedullary nailing of femoral and tibial diaphyseal fractures. A range of sensitive neuropsychological tests were then applied after surgery to assess for any clinical cognitive change. Any correlation between the intra-operative cerebral embolic load and cognitive function was then established. Our hypothesis was that the level of cerebral embolisation would be lower than that required to consistently produce cognitive change.

Section snippets

Materials and methods

Local Research Ethical Committee approval and written consent from each patient was obtained (LREC No. 2003/R/OST/02). Twenty non-consecutive patients with a median age of 38 years (range 17–79) were recruited by the primary investigator after admission to the orthopaedic trauma unit. Inclusion criteria were femoral or tibial diaphyseal fractures that required intramedullary stabilisation under general anaesthesia. Exclusion criteria included patients aged under 16 or greater than 80 years and

Statistical methods

All information was recorded and analysed using the SPSS software package version 11.0 (SPSS, Inc., Chicago, Illinois). Each cognitive test result was expressed as a percentile difference compared to the predicted pre-morbid score (PFSIQ (%)). A Wilcoxon signed-rank test was then used to determine if this difference was significant (p value < 0.05).

Mann–Whitney U tests compared the median cognitive test score differences of patients who had cerebral embolic events and those who did not. This was

Cerebral emboli detection

Four patients had detectable cerebral embolic events with counts of only 2, 3, 3 and 9 respectively. The highest cerebral embolic load occurred after intramedullary fixation of a pathological femoral fracture secondary to a metastatic deposit from small-cell lung neoplasia. The other three patients had isolated tibial fractures. The distributions of embolic events over the phases of each stabilisation procedure are demonstrated in Fig. 1. The majority were detectable during and immediately

Discussion

Specific and quantifiable defects in cognitive function were detectable after surgery. First, patients performed significantly worse than predicted on a test, which required them to repeat number sequences of increasing length (digit span). Secondly, patients performed more poorly than would have been anticipated on a test of verbal recall in both immediate and delayed conditions. Furthermore, interference scores indicated that memory consolidation was adversely affected by the presentation of

Conclusions

A relatively small volume of cerebral embolus was detected predominantly during the intramedullary instrumentation phase of long bone fracture stabilisation. No direct correlation was found between this embolic load and the poorer cognitive results detected using the more sensitive clinical tests. This poor correlation is similar to recent studies involving arthroplasty patients and conforms to the cardiac surgery literature where such low levels of systemic embolisation would be unlikely to

Conflict of interest statement

No benefits in any form have been received or will be received from a commercial party related to the subject of this article by any of the authors. There are no conflicts of interest from any of the authors with regards this study.

References (22)

M.F. Folstein et al.
Mini-mental state. A practical method for grading the cognitive state of patients for the clinician
J Psychiatr Res
(1975)
J. Kilo et al.
Cardiopulmonary bypass affects cognitive brain function after coronary artery bypass grafting
Ann Thorac Surg
(2001)
R.A. Rodriguez et al.
Cognitive dysfunction after total knee arthroplasty: effects of intraoperative cerebral embolization and postoperative complications
J Arthroplasty
(2005)
O.A. Selnes et al.
Neurobehavioural sequelae of cardiopulmonary bypass
Lancet
(1999)
R.J. Byrick et al.
Transpulmonary systemic fat embolism. Studies in mongrel dogs after cemented arthroplasty
Am J Respir Crit Care Med
(1994)
J. Christie et al.
Intramedullary locking nails in the management of femoral shaft fractures
J Bone Joint Surg Br
(1988)
J. Christie et al.
Transcardiac echocardiography during invasive intramedullary procedures
J Bone Joint Surg
(1995)
C.M. Court-Brown et al.
Closed intramedullary tibial nailing. Its use in closed and type I open fractures
J Bone Joint Surg Br
(1990)
L. D’Elia et al.
Color trails test
(1989)
A.M. Forteza et al.
Transcranial doppler detection of fat emboli
Stroke
(1999)

A.C. Gray et al.

The cognitive effects of fat embolus syndrome following an isolated femoral shaft fracture. A case report

J Bone Joint Surg Am

(2007)

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Citation Excerpt :
However, although reamed intramedullary nailing has long been considered a safe procedure, pulmonary complications have been reported in some groups of patients.14,24,31 Concerns over fat embolisation, adult respiratory distress syndrome (ARDS), sudden intraoperative death and aseptic cortical thermal necrosis have prompted some authors to question whether the benefits of reaming are outweighed by its potential adverse effects to the patient.5,6,10,21,13,27,33,45,5,15,19,49 In response to these complications, recent evaluations have focused on alternative systems that reduce intramedullary pressure during reaming.35,39
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Cerebral emboli and cognitive function after intramedullary fracture fixation

Abstract

Introduction

Patients and methods

Results

Discussion

Introduction

Section snippets

Materials and methods

Statistical methods

Cerebral emboli detection

Discussion

Conclusions

Conflict of interest statement

J Psychiatr Res

Ann Thorac Surg

J Arthroplasty

Lancet

Transpulmonary systemic fat embolism. Studies in mongrel dogs after cemented arthroplasty

Am J Respir Crit Care Med

Intramedullary locking nails in the management of femoral shaft fractures

J Bone Joint Surg Br

Transcardiac echocardiography during invasive intramedullary procedures

J Bone Joint Surg

Closed intramedullary tibial nailing. Its use in closed and type I open fractures

J Bone Joint Surg Br

Color trails test

Transcranial doppler detection of fat emboli

Stroke

The cognitive effects of fat embolus syndrome following an isolated femoral shaft fracture. A case report

J Bone Joint Surg Am