Cement implantation syndrome: a time limited embolic phenomenon

Study of the cement implantation syndrome: A review

Bone cement implantation syndrome (BCIS) is a critical and potentially life-threatening condition that manifests during implantation. Characterized by a constellation of symptoms, including hypoxemia, hypotension, cardiac arrhythmias, elevated pulmonary vascular resistance, and occasionally cardiac arrest, BCIS typically ensues shortly after cement introduction, albeit with rare instances of delayed onset. Primarily attributed to the exothermic reaction of bone cement implantation, this syndrome is caused by local tissue damage, histamine and prostaglandin release, and microemboli formation, ultimately triggering a systemic immune response that culminates in respiratory and circulatory failure. The current hypotheses regarding BCIS include embolism, allergic reactions, and cement autotoxicity. BCIS management emphasizes preventative strategies, encompassing meticulous patient risk assessment, comprehensive preoperative and intraoperative evaluations, and precise cement application techniques. Treatment primarily involves symptomatic therapy and life-support measures to address the systemic effects of the syndrome.

Severe Hemodynamic Collapse During Humerus Stabilization with Photodynamic Implant: A Report of Two Cases

CASE

We present 2 cases of severe hemodynamic collapse during prophylactic stabilization of impending pathologic humerus fractures using a photodynamic bone stabilization device. Both events occurred when the monomer was infused under pressure into a balloon catheter.

CONCLUSION

We suspect that an increase in intramedullary pressure during balloon expansion may cause adverse systemic effects similar to fat embolism or bone cement implantation syndrome. Appropriate communication with the anesthesia team, invasive hemodynamic monitoring, and prophylactic vent hole creation may help mitigate or manage these adverse systemic effects.

Bone Cement and Its Anesthetic Complications: A Narrative Review

The concept of bone cement implantation syndrome (BCIS) is not yet fully understood. In patients undergoing cemented hip arthroplasty, it is a significant factor in intraoperative mortality and morbidity. It may also manifest in a milder form postoperatively, resulting in hypoxia and confusion. In the older population, hip replacement surgery is becoming more prevalent. The risks of elderly patients suffering BCIS may be increased due to co-existing conditions. In this article, we present a narrative review of BCIS including its definition, incidence, risk factors, etiology, pathophysiology, clinical features, prevention, and management, all from an anesthetic point of view.

Bone Cement Implantation Syndrome in Bone Tumor Surgeries: Incidence, Risk Factors, and Clinical Experience

Objective

To investigate the incidence and risk factors of bone cement implantation syndrome (BCIS) in bone tumor surgeries.

Methods

This was a retrospective observational study. We investigated patients who underwent bone tumor surgeries requiring cementation as part of the surgery between March 2016 and January 2018. We reviewed medical records, including formal anesthesia records and operation notes. Patients with complete data files were included. To investigate the general incidence of BCIS in tumor surgeries, patients of all ages, genders and tumor types were included. Vital signs, including oxygen saturation, blood pressure, heart rate, and respiratory rate, were checked and recorded once every 1–2 min after cementation. Accurate time points of cementation were recorded on formal anesthesia record sheets by the anesthesiologists. The definition and severity of BCIS were based on the classification system proposed in previous studies: grade I, moderate hypoxia (SpO₂ <94%) or hypotension (fall in systolic blood pressure >20%); grade II, severe hypoxia (SpO₂ <88%) or hypotension (fall in systolic blood pressure >40%) or unexpected loss of consciousness; and grade III, cardiovascular collapse requiring cardiopulmonary resuscitation. We also compared the incidence of BCIS between those patients with and without possible risk factors, including intraoperative blood loss, arthroplasty, use of an intramedullary device, patient age, gender, tumor location, and preexisting lung cancer or lung metastasis.

Results

A total of 88 patients were included. BCIS occurred in 23 patients, with an incidence of 26.1%. Among them, 19 had grade I and 4 had grade II BCIS. There was no patients with grade III BCIS. The lowest blood pressure occurred within 10 min in 21 (87.5%) patients and within 20 min for all patients. A total of 9 grade I BCIS were self‐limiting. The other 10 grade I hypotension cases and all grade II hypotension cases recovered after administration of a vasoconstrictor medication. Preexisting lung cancer or lung metastasis was the risk factor for BCIS; 40.0% of patients (16 in 40 patients) with preexisting lung cancer or metastasis had BCIS, whereas only 14.6% of patients (7 in 48 patients) without lung lesions had BCIS. There was no risk difference in terms of arthroplasty, old age, and increased blood loss. Apart from grades I and II bone cement implantation syndrome, there were no other major complications, including death, cardiovascular events, or cerebrovascular events.

Conclusion

Bone cement implantation syndrome is not unusual in bone tumor surgeries, and preexisting lung cancer or lung metastasis is a risk factor.

Inhaled prostacyclin for the prevention of increased pulmonary vascular resistance in cemented hip hemiarthroplasty-A randomised trial

BACKGROUND

Bone cementation may cause pulmonary vasoconstriction and ventilation/perfusion abnormalities in patients undergoing cemented hip hemiarthroplasty. In this randomised trial, we tested the hypothesis that intra-operative inhalation of prostacyclin could attenuate the increase in pulmonary vascular resistance index (PVRI, primary endpoint) when compared to inhaled saline in this group of patients.

METHODS

Twenty-two patients with displaced femoral neck fractures were allocated to receive inhaled aerosolised prostacyclin (20 ng/kg/min) (n = 11) or inhaled saline (NaCl, 9 mg/mL) (n = 11). All patients received total intravenous anaesthesia and were catheterised with radial and pulmonary artery fast response thermodilution catheters, for measurements of arterial and pulmonary arterial pressures, cardiac output, right ventricular ejection fraction and effective pulmonary arterial elastance. Haemodynamic measurements were performed after induction of anaesthesia, during surgery before and immediately after bone cementation and prosthesis insertion, 10 and 20 min after insertion and during skin closure.

RESULTS

During the surgical procedure, PVRI increased both in the saline (44%, P < 0.001) and the prostacyclin (36%, P = 0.019) groups, with a less pronounced increase in the prostacyclin group (P = 0.031). Effective pulmonary arterial elastance increased both in the saline (44%, P < 0.001) and the prostacyclin groups (29%, P = 0.032), with a trend for a less pronounced increase in the prostacyclin group (P = 0.084). Right ventricular ejection fraction decreased significantly in both groups with no difference between the groups.

CONCLUSION

Inhalation of prostacyclin attenuates the increase in pulmonary vascular resistance in patients undergoing cemented hip hemiarthroplasty and could potentially attenuate/prevent haemodynamic instability induced by an increase in right ventricular afterload seen in this procedure.

Occurrence, risk factors, and outcomes of bone cement implantation syndrome after hemi and total hip arthroplasty in cancer patients

BACKGROUND AND OBJECTIVES

Patients undergoing cement fixation for hip arthroplasty are at increased risk of developing bone cement implantation syndrome (BCIS). We sought to determine: what is the occurrence of BCIS in patients with cancer after hip arthroplasty? What are the risk factors in patients with cancer for the development of this syndrome? What is the outcome for patients with cancer having BCIS?

METHODS

We identified 374 patients with cancer who underwent cemented hip arthroplasty between 2010 and 2014. Patient characteristics, operative variables, and outcomes were collected.

RESULTS

BCIS occurred in 279 (75%) patients. A total of 353 (94%) patients had bone metastases and 179 (48%) patients had lung metastases at the time of surgery. Age greater than 60 (hazard ratio [HR] 2.09, P = .02) and the presence of lung metastases (HR 1.77, P = .019) were associated with increased risk of BCIS. Increased perioperative use of vasopressors (HR 1.72, P = .023) and increased hospital stay beyond 10 days (HR 2.67, P = .003) was associated with BCIS.

CONCLUSIONS

BCIS is a frequent clinical event in patients with cancer undergoing femoral cemented arthroplasty with increased risk for patients over age 60 and those with compromised lung function due to lung metastases and lung cancer. Patients who develop BCIS are more likely to require longer postoperative hospitalization. Careful preoperative assessment and intraoperative communication are crucial steps to reduce the consequences of BCIS.

Pulmonary haemodynamics and right ventricular function in cemented vs uncemented total hip arthroplasty-A randomized trial

BACKGROUND

Bone cement implantation syndrome (BCIS) is a feared complication in orthopaedic surgery with a huge impact on post-operative morbidity. In this randomized trial, we evaluated the effects of bone cement on pulmonary and systemic haemodynamics in patients receiving either cemented or uncemented hip arthroplasty for isolated femoral neck fracture.

METHODS

Twenty-two patients were randomized to receive either cemented (n = 10) or uncemented (n = 12) total hip arthroplasty. Surgery was performed under total intravenous anaesthesia in the lateral position. All patients were catheterized with radial- and pulmonary artery catheters, for continuous measurements of mean arterial pressure (MAP), pulmonary arterial pressure (PAP), cardiac output, right ventricular (RV) end-diastolic volume (RVEDV) and RV ejection fraction (RVEF). Haemodynamic measurements and blood gas analyses were performed after induction of anaesthesia, during surgery before and immediately after bone cementation and prosthesis insertion, 10 and 20 minutes after insertion and during skin closure.

RESULTS

Pulmonary vascular resistance index (PVRI) increased during and after prosthesis insertion by 45% and 20% in the cemented and uncemented group, respectively (P < 0.005). Systolic and mean PAP increased by 18% and 17% in the cemented group, which was not seen in the uncemented group (P < 0.001). There was a trend for a more pronounced fall in RVEF in the cemented group, while there were no differences in cardiac output or stroke volume between groups.

CONCLUSION

The use of bone cement in total hip arthroplasty increases pulmonary vascular resistance and the afterload of the RV with potentially negative effects on RV performance.

Comparison between Colloid Preload and Coload in Bone Cement Implantation Syndrome under Spinal Anesthesia: A Randomized Controlled Trial

Background:

Bone cement implantation syndrome (BCIS) is characterized by hypoxia hypotension cardiac arrest. There is not any research that investigated the hemodynamic effects of colloid use during and before cement implantation regarding BCIS development.

Aims:

We aimed to compare the effects of colloid preloading before or coloading simultaneously at cement implantation on BCIS development and hemodynamic parameters in patients who underwent total knee arthroplasty.

Settings and Design:

This is a prospective, randomized, clinical trial with the participation of 109 patients over 60 years of age and patients physical status American Society of Anesthesiologists Classes I and II to undergo knee surgery. The patients were administered spinal anesthesia, divided into three groups.

Subjects and Methods:

The patients in Group I were infused 8 mL/kg hydroxyethyl starch (130/0.4) 20 min before the cement implantation, those in Group II were infused the same simultaneously during cement implantation. Group III was infused 8 mL/kg/h sodium chloride during the anesthesia management. Hemodynamic parameters of the patients were recorded at before and after cement implantation and once the tourniquet was removed.

Statistical Analysis Used:

The descriptive statistics were presented as the mean ± standard deviation for normally distributed variables, as the median for nonnormally distributed variables, and as the number of cases and (%) for nominal variables. Pearson's Chi-square test and Fisher's exact test were used in the analysis of categorical variables.

Results:

Compared to the control group, Groups I and II were hemodynamically more stable. The development of moderate hypoxia during cement implantation was significantly different between the study groups (P < 0.05).

Conclusions:

We suggest that avoiding intravascular volume depletion by using the colloids, particularly in elderly patients, is important for preventing from the BCIS.

Cardiovascular ultrasonography detection of embolic sources in trauma

Venous thromboembolism (deep vein thrombosis and pulmonary embolism) and bone cement implantation syndrome are major sources of embolic events in trauma patients. In these patients, embolic events due to venous thromboembolism and bone cement implantation syndrome have been detected with cardiac and vascular ultrasonography in the emergency setting, during the perioperative period, and in the intensive care unit. This article discusses the ultrasonography modalities and imaging findings of embolic events related to venous thromboembolism and bone cement implantation syndrome. The aim is to present a short review with exceptional illustrations that can enable physicians to identify sources of emboli in trauma patients with cardiovascular ultrasonography.

Complications With Long Cemented Stems in Proximal Femoral Replacement

This study attempted to determine whether patients undergoing cemented long-stem proximal femoral replacement had: (1) an increased short-term mortality rate; (2) greater intraoperative hemodynamic instability; (3) a greater need for resuscitation; and (4) a decreased risk of periprosthetic fracture. The current study reviewed intraoperative and short-term events related to clinical outcomes in 24 consecutive patients who were treated at a single institution over a 5-year period. These patients underwent primary long-stem (≥250 mm, n=13) vs short-stem (<250 mm, n=11) cemented proximal femoral replacement. Other than stem length, the 2 groups were not significantly different in terms of patient age, sex, height, weight, body mass index, diagnosis, or preoperative American Society of Anesthesiologists functional score. Primary outcomes were intraoperative death, blood loss, blood transfusions, fluid resuscitation, hypotension, oxygen desaturation, mortality up to 1 year, and need for revision surgery. At 1 year, a significantly increased mortality rate (77% vs 27%, P=.03) was noted in patients receiving long-stem vs short-stem arthroplasty. Patients who received longer stems also required more intraoperative blood transfusions and fluid resuscitation (P=.04) for greater hypotension (P=.04) and oxygen desaturation (P=.04). Two intraoperative deaths occurred in the long-stem group, and none occurred in the short-stem group. The findings suggest that there is an increased risk of intraoperative hemodynamic instability with long-stem vs short-stem proximal femoral replacement, with a need for greater resuscitative efforts and an increased risk of mortality at 1 year. [Orthopedics. 2016; 39(3):e423-e429.].

An Experimental Study to Determine the Role of Inferior Vena Cava Filter in Preventing Bone Cement Implantation Syndrome

BACKGROUND

Inferior vena cava filters (IVCF) are frequently used for preventing pulmonary embolism (PE) following deep venous thromboembolism.

OBJECTIVES

The present study was designed to investigate whether IVCF could prevent or impede the occurrence of bone cement implantation syndrome (BCIS), since PE is considered as the central mechanism of BCIS.

MATERIALS AND METHODS

Fifteen sheep were divided into three groups: bone cement free (BCF) group, cement implantation (CI) group and IVCF group. In all the groups, an osteotomy proximal to the greater trochanter of left femur was carried out. In BCF group, the femoral canal was not reamed out or packed with any bone cement. In CI and IVCF groups, the left femoral canals were packed with bone cement, to simulate the cementing procedures carried out in hip replacement. An OptEase(®) filter was placed and released in inferior vena cava, prior to packing cement in the femoral canal in IVCF group, while the IVCF was not released in the CI group. The BCF group was considered as control.

RESULTS

Systolic blood pressure (SBP), saturation of oxygen (SaO2) and partial pressure of carbon dioxide (PaCO2) declined significantly 10 min after the bone cement packing, in CI group, compared to those in BCF group. This was accompanied by a rise in the arterial pH. However, IVCF prevented those changes in the CI group. On ultrasonography, there were dotted echoes in right atrium in the CI group, after bone cement packing, while such echoes were hardly seen in the IVCF group.

CONCLUSION

This study demonstrates that IVCF could prevent BCIS effectively, and, as a corollary, suggests that PE represents the leading cause of the constellation of BCIS symptoms.

Systemic effects of polymethylmethycrylate in total knee replacement: A prospective case-control study

OBJECTIVE

Mortality rates reported by the National Joint Registry for England and Wales (NJR) were higher following cemented total knee replacement (TKR) compared with uncemented procedures. The aim of this study is to examine and compare the effects of cemented and uncemented TKR on the activation of selected markers of inflammation, endothelium, and coagulation, and on the activation of selected cytokines involved in the various aspects of the systemic response following surgery.

METHODS

This was a single centre, prospective, case-control study. Following enrolment, blood samples were taken pre-operatively, and further samples were collected at day one and day seven post-operatively. One patient in the cemented group developed a deep-vein thrombosis confirmed on ultrasonography and was excluded, leaving 19 patients in this cohort (mean age 67.4, (sd 10.62)), and one patient in the uncemented group developed a post-operative wound infection and was excluded, leaving 19 patients (mean age 66.5, (sd 7.82)).

RESULTS

Both groups had a similar response with regards to the levels of C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-alpha (TNFα). CD40 levels rose significantly on the cemented group over day one to day seven compared with that of the uncemented group, which occurred over the first 24 hours. The CD14/42a levels demonstrated a statistically significant increase in the cemented group (p < 0.001 first 24 hours and p = 0.02 between days one and seven).

CONCLUSIONS

The uncemented and cemented groups demonstrated significant changes in the various parameters measured at various time points but apart from CD14/42a levels, there was no significant difference in the serum markers of inflammation, coagulation and endothelial dysfunction following cemented TKR. Cite this article: Bone Joint Res 2014;3:108-16.

Safety and efficacy of non-cemented femoral fixation in patients 75 years of age and older

The aim of this study was to assess peri-operative complications, safety and efficacy of non-cemented femoral fixation in total hip arthroplasty (THA) as compared to cemented femoral fixation in the elderly population. Fifty-two matched pair analysis of patients with 75 years of age and older (104 patients), who underwent primary THA from June 1997 to December 2004, was performed based on age, sex, BMI, and Charnley classification. Mean age was 81 years (75-101) and the average follow up was 3.1 ± 2.9 years (1.2-6.4). There was no difference in peri-operative cardiopulmonary complications, pulmonary failures, deep venous thrombosis, pulmonary embolus, length of stay, or discharge deposition between the two groups. Non-cemented fixation is safe and effective in patients older than 75 years of age.

Is there a difference in perioperative mortality between cemented and uncemented implants in hip fracture surgery?

INTRODUCTION

Although cemented implants have proven beneficial over uncemented implants for treatment of displaced sub-capital proximal femoral fractures, there are concerns regarding the haemodynamic consequence of using cemented implants in hip fracture patients. National Patient Safety Agency recently issued an alert regarding the use of cement in hip fracture surgery. We compared the incidence and pattern of 48 h perioperative mortality between patients receiving cemented and uncemented implants after hip fracture surgery.

METHODS

Using data prospectively recorded in hospital care records, we retrospectively reviewed the case records of all patients who died in hospital following hip fracture surgery between January 2005 and April 2010. We recorded demographic variables, type of fracture, implant used, medical co-morbidity, seniority of operating surgeon and anaesthetist, perioperative haemodynamic status, time and cause of death.

RESULTS

We identified 15 cases of perioperative death (PoD) over a 64-month period. PoD was 1% (15/1402). Eight of 15 deaths occurred following cemented hemiarthroplasty insertion. There were four cases of intra-operative death, two of them were following cemented hemiarthroplasty insertion. PoD following cemented hemiarthroplasty was 2.54% (8/314) and nil (0/168) following uncemented Austin-Moore hemiarthroplasty. Operations were performed by both trainees (six) and consultants (two). Both trainees (five) and consultants (three) anaesthetised the patients. None of the patients belonged to American Society of Anesthesiologists (ASA) I or II (ASA III 5 and IV 3). All patients had significant cardiovascular or pulmonary co-morbidity. Apart from the cases of immediate haemodynamic collapse and death, cemented implant insertion was followed by intra-operative haemodynamic instability in 2/15 and perioperative instability in 3/15 patients. Post-mortem was performed in 3/8 patients: 2/3 demonstrated pulmonary embolism (PE), 1/3 bronchopneumonia. Of the rest, 3/5 had suspected myocardial infarction (MI).

CONCLUSION

There was 1% risk of perioperative death after hip fracture surgery. Risk of perioperative death was significantly higher following cemented implant insertion. Mortality risk was exacerbated in patients with pre-existing cardiovascular morbidity and was independent of the seniority of the surgeon or the anaesthetist.

Phosphorylated Pullulan Bioadhesive for Regeneration and Reconstruction of Bone and Tooth

A biodegradable material that bonds to hard tissues such as bones and teeth is urgently needed for medical and dental applications. However, such materials are not available in today’s clinical practice of orthopedics and dentistry. Therefore, we synthesized biodegradable phosphorylated pullulan to develop a biomaterial that combines primary properties such as high biocompatibility, good bonding potential to hard tissue, high strength, biodegradability, and osteoconductivity. The pharmacopoeial polysaccharide pullulan was chemically functionalized with dihydrogen phosphate groups. Phosphorylated pullulan was formed network by adding calcium ion, making the composite less soluble in water. Adhesive force measurement revealed that adhesiveness of the pastes before setting can be controlled through optimization of additives. In addition, histological evaluation revealed that phosphorylated pullulan-based composite possesses high biocompatibility. These results indicate that phosphorylated pullulan can be used as a key material for regeneration and reconstruction of bone and tooth.

Noise-enhanced clustering and competitive learning algorithms

Noise can provably speed up convergence in many centroid-based clustering algorithms. This includes the popular k-means clustering algorithm. The clustering noise benefit follows from the general noise benefit for the expectation-maximization algorithm because many clustering algorithms are special cases of the expectation-maximization algorithm. Simulations show that noise also speeds up convergence in stochastic unsupervised competitive learning, supervised competitive learning, and differential competitive learning.

Mortality and implant revision rates of hip arthroplasty in patients with osteoarthritis: registry based cohort study

OBJECTIVES

To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing.

DESIGN

Cohort study.

SETTING

National Joint Registry.

POPULATION

About 275,000 patient records.

MAIN OUTCOME MEASURES

Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity.

RESULTS

As there were large baseline differences in the characteristics of patients receiving cemented, uncemented, or resurfacing procedures, unadjusted comparisons are inappropriate. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Both uncemented total hip replacements and Birmingham hip resurfacings had a higher revision rate than cemented total hip replacements.

CONCLUSIONS

There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation.

Cementless bipolar hemiarthroplasty in femoral neck fractures in elderly

BACKGROUND

Cemented hip arthroplasty is an established treatment for femoral neck fracture in the mobile elderly. Cement pressurization raises intramedullary pressure and may lead to fat embolization, resulting in fatal bone cement implantation syndrome, particularly in patients with multiple comorbidities. The cementless stem technique may reduce this mortality risk but it is technically demanding and needs precise planning and execution. We report the perioperative mortality and morbidity of cementless bipolar hemiarthroplasty in a series of mobile elderly patients (age >70 years) with femoral neck fractures.

MATERIALS AND METHODS

Twenty-nine elderly patients with mean age of 83 years (range:71-102 years) with femoral neck fractures (23 neck of femur and 6 intertrochanteric) were operated over a 2-year period (Nov 2005-Oct 2007). All were treated with cementless bipolar hemiarthroplasty. Clinical and radiological follow-up was done at 3 months, 6 months, 12 months, and then yearly.

RESULTS

The average follow-up was 36 months (range 26-49 months). The average duration of surgery and blood loss was 28 min from skin to skin (range, 20-50 min) and 260 ml (range, 95-535 ml), respectively. Average blood transfusion was 1.4 units (range, 0 to 4 units) Mean duration of hospital stay was 11.9 days (7-26 days). We had no perioperative mortality or serious morbidity. We lost two patients to follow-up after 12 months, while three others died due to medical conditions (10-16 months post surgery). Twenty-four patients were followed to final follow-up (average 36 months; range: 26-49 months). All were ambulatory and had painless hips; the mean Harris hip score was 85 (range: 69-96).

CONCLUSION

Cementless bipolar hemiarthroplasty for femoral neck fractures in the very elderly permits early return to premorbid life and is not associated with any untoward cardiac event in the perioperative period. It can be considered a treatment option in this select group.

What Is Wrong in the Cava? A Rare Cause of Deep Vein Thrombosis

When using cement in a hip arthroplasty, high intramedullary pressures are generated. This may lead to several complications, ranging from local extravasation to systemic complications such as the implantation syndrome. Until now, venous migration of cement after hip arthroplasty has never been associated with morbidity or mortality. We present a case in which cement pressurization lead to migration of cement up to the level of the inferior vena cava with subsequent deep vein thrombosis.

Bone cement implantation syndrome

Bone cement implantation syndrome (BCIS) is poorly understood. It is an important cause of intraoperative mortality and morbidity in patients undergoing cemented hip arthroplasty and may also be seen in the postoperative period in a milder form causing hypoxia and confusion. Hip arthroplasty is becoming more common in an ageing population. The older patient may have co-existing pathologies which can increase the likelihood of developing BCIS. This article reviews the definition, incidence, clinical features, risk factors, aetiology, pathophysiology, risk reduction, and management of BCIS. It is possible to identify high risk groups of patients in which avoidable morbidity and mortality may be minimized by surgical selection for uncemented arthroplasty. Invasive anaesthetic monitoring should be considered during cemented arthroplasty in high risk patients.

[Pulmonary embolism of cement during vertebroplasty]

A 62-year-old woman with severe osteoporosis experienced pulmonary embolism by polymethylmethacrylate after percutaneous vertebroplasty. The patient immediately developed respiratory and cardiac distress, and a computed tomographic scan revealed the presence of cement in the pulmonary circulation. Proper techniques can minimize the risk of pulmonary embolism during percutaneous vertebroplasty: adequate preparation of cement and fluoroscopy during the procedure are recommended.

Reduction of Toxic Effect of Methyl Methacrylate on Human Cells in Culture Containing Sodium Hypochlorit

The effect of sodium hypochlorite (SH) upon toxic response of cultured human fibroblasts to methyl methacrylate (MMA) which is a part of bone cement «Polacris» has been studied. Toxic effect of MMA in clinically adequate concentrations demonstrated dose-dependant suppression of total activity of mitochondrial enzymes and that was one of the showings of stress at the cellular level. MMA:SH mixture in volume ratio 1:1 and 10:1 caused reliable reduction of toxic effect on cultured cells as compared with pure MMA of the similar concentration. On the contrary, MMA: SH mixture in volume ratio 1:10 resulted in true decrease of fibroblasts viability as compared with the state of cells in presence of pure MMA. Thus it was shown that chemical experimental in vitro inactivation of MMA could be achieved only when MMA concentration was either higher or equal to SA concentration. That provided the reduction of metabolic disturbances in cells.

Cardiopulmonary complications of intramedullary fixation of long bone metastases

Intramedullary fixation of long bone metastases is an effective method of treating or preventing pathologic fractures. An important complication of this technique is the development of pulmonary embolism, which may occur at any number of steps during bone manipulation. Passage of normal marrow contents or tumor into the pulmonary circulation is thought to cause various biochemical, hemodynamic, or physical responses that lead to hypotension, arrythmia, and O2 desaturation. Death is a known risk of this procedure. Numerous surgical and anesthetic strategies have been developed to prevent or treat pulmonary embolic phenomena; however, the most important prophylaxis may be a heightened awareness of this possibility during any procedure that involves intramedullary manipulation of tumor containing bone.

A lethal pulmonary embolism during percutaneous vertebroplasty

IMPLICATIONS

This case report describes a fatal cardiac arrest during percutaneous vertebroplasty. This serves to remind us that life threatening intraoperative pulmonary embolism may occur in this minimal invasive procedure. Surgical precautions and invasive cardiovascular monitoring may be required in high-risk patients.

Adverse clinical events during cemented long-stem femoral arthroplasty

The occurrence and risk factors for adverse clinical events associated with cemented long-stem femoral arthroplasty were studied. The hypothesis was that patients with femoral metastatic disease and previously uninstrumented canals were at higher risk for such adverse events. Fifty-five consecutive patients requiring long-stem femoral arthroplasty at two institutions were retrospectively reviewed. Adverse clinical events including hypotension, sympathomimetic administration, and O 2 desaturation were subclassified according to the timing of their occurrence. Adverse events occurred in 34 of 55 patients (62%), including coma in two patients and death in a third patient. The three catastrophic events occurred in patients with metastatic disease involving previously uninstrumented femoral canals. Desaturation was more frequent in patients with metastatic disease and previously uninstrumented canals compared with patients who had revision arthroplasty and patients with previously instrumented femoral canals. Preexisting medical illness was a significant risk factor in total adverse clinical events that included cement-associated adverse clinical events and cement-associated and postoperative hypotension. In long-stem cemented femoral components risk factors for adverse clinical events included metastatic disease, uninstrumented femoral canals, and preexisting medical conditions. These findings underscore the importance of appropriate patient selection, patient and family education, and anesthesia preparation before long-stem cemented femoral arthroplasty.

Intraosseous lidocaine provides effective analgesia for percutaneous vertebroplasty of osteoporotic fractures

PURPOSE

To assess the safety and efficacy of intraosseous lidocaine (IL), in comparison with iv nalbuphine and propacetamol (NP) for analgesia during percutaneous vertebroplasty (PV) in order to avoid general anesthesia in elderly patients.

METHODS

Patients (age 68 +/- 13 yr, weight 66 +/- 6 kg) undergoing PV for osteoporotic fractures were randomized prospectively into two groups: NP (n=50) and IL (n=50). All patients were premedicated (oral hydroxyzine 1 mg.kg(-1)) and had skin infiltration with 5 mL of 1% lidocaine prior to vertebral puncture. Thirty minutes before the procedure, Group NP received, in a blinded manner, 50 mL of iv nalbuphine (0.3 mg.kg(-1)) and propacetamol (30 mg.kg(-1)) while Group IL received 50 mL of iv saline. During vertebral puncture, Groups NP and IL received, in a blinded manner, 1 mL.10 kg(-1) of intraosseous saline and 1% lidocaine respectively. Pain was assessed during vertebral puncture and cement injection with a four-point verbal rating scale. Additionally, lidocaine plasma kinetics were obtained in 11 IL patients.

RESULTS

Analgesic efficacy was similar in the IL and NP groups (85 vs 84%). Group NP had more side effects. Lidocaine peak recorded concentration was 2.6 +/- 0.1 microg.mL(-1) i.e., about three times less than the reported toxic limits.

CONCLUSION

IL is as effective as the association of iv NP for analgesia in PV. However, considering that both protocols were insufficient in about 15% of cases, other modalities are needed to further improve analgesia and avoid general anesthesia during vertebroplasty.

Amniotic fluid embolus: a review of the literature

PURPOSE

To review the literature since 1979 to determine the natural history, etiology, diagnosis and potential treatment of amniotic fluid embolus (AFE).

SOURCE

English language articles and books published between June 1976 and June 1998 were identified by a computerized medline search using the title or text word amniotic fluid embolus. This same search strategy was repeated and updated to October 1999 by an independent individual using both Medline and Embase. The search was also expanded to include Science Citation Index listing Morgan's 1979 review article. All relevant publications were retrieved and their bibliographies were scanned for additional sources.

PRINCIPAL FINDINGS

Randomized controlled trials are not possible with amniotic fluid emboli. The majority of the literature consists of clinical reports combined with occasional limited reviews. Knowledge obtained from these reports suggests that amniotic fluid emboli present as a spectrum of disease that ranges from a subclinical entity to one that is rapidly fatal. Because cases are sporadic and the diagnosis is often unconfirmed, little progress has been made towards understanding its etiology or defining the risk factors. Present management is empirical and directed towards the maintenance of oxygenation, circulatory support and the correction of coagulopathy.

CONCLUSION

Amniotic fluid embolus continues to be a life-threatening but potentially reversible complication unique to pregnancy. It cannot be predicted nor prevented. Review of the literature reveals that there are no standardized investigational methods or protocols to confirm the diagnosis in suspected cases.

Cerebral embolization presenting as delayed, severe obtundation in the postanesthesia care unit after total hip arthroplasty

Catastrophic neurologic events occur rarely postoperatively and must be diagnosed quickly. A 63-year-old woman who had undergone uneventful total hip arthroplasty experienced obtundation after admission to the postanesthesia care unit. Cranial magnetic resonance imaging revealed multiple lesions consistent with ischemia or infarction, and fat cerebral embolism was diagnosed. We describe the numerous complications that may occur in patients in the postanesthesia care unit and review the differential diagnosis of altered mental status in such patients. Paradoxical cerebral fat embolization must be considered in the differential diagnosis of altered mental status after pelvic or long bone fracture or lower extremity major joint replacement, and this condition may occur despite normal pulmonary function and no patent foramen ovale or right-to-left intracardiac shunt. Magnetic resonance imaging with T2-weighted sequences is the cranial imaging study of choice for early evaluation of patients with sudden multifocal neurologic deficits and suspected fat embolism syndrome.

The incidence of acute cardiorespiratory and vascular dysfunction following intramedullary nail fixation of femoral metastasis

Intramedullary nail fixation is a common treatment for metastatic tumors of the femur with overt or impending femoral fracture. This procedure sometimes causes severe cardiorespiratory and vascular dysfunction. The clinical relevance of this is not dear. We reviewed 45 operations in 43 patients, where intramedullary nail fixation was used to treat metastatic femoral fractures and impending fractures. We studied the incidence of intraoperative oxygen desaturation and hypotension associated with intramedullary manipulation as markers of cardiorespiratory and vascular dysfunction. Acute oxygen desaturation and hypotension occurred in 11 of our 45 patients. Of these, 3 died, 2 required intensive care postoperatively and 6 made uneventful recoveries. We hope to highlight a serious complication in this patient group.

The cost for construction and operation of a simulation centre

PURPOSE

Lack of financial information results in planning difficulties and may delay the introduction of simulator based education. We collected data from an existing simulation centre and describe a construction and operating budget to facilitate planning and construction for interested institutions.

METHODS

After obtaining approval from the managing board, the plans and financial statements of the Canadian Simulation Centre, Sunnybrook Health Science Centre, University of Toronto were reviewed from the period from July 1994 through June 1996. Costs were calculated from the financial reports and separated into construction and operation phases. A list of the ongoing educational and research activities was compiled.

RESULTS

All dollar figures are expressed in 1996 Canadian Dollars. The planning and construction took place from July 1994 through June 1995. Construction costs for the simulation centre totalled $665,000, of which 85% was related to capital equipment purchases and 15% for salary support. The net costs of ongoing education and research activities (3.35 days/week) were $167,250 from July 1995 through June 1996. About 65% of this consisted of salary support and was absorbed by the existing educational resources of the University of Toronto Department of Anaesthesia.

CONCLUSION

Substantial resources are required for the construction of a simulation centre ($665,000) primarily use of capital equipment purchases. However, there is also a considerable operating cost per year ($167,250) which consists mostly of salary support.