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loss during orthognathic surgery?
Is operating time correlated to blood loss and/or
blood transfusion?
Is blood loss related to blood transfusion?
Is an evolution in time detectable concerning
duration of operations and/or blood loss?
The methodological questions that need to be
answered are as follows:
How is blood loss defined or measured?
How is operation time defined?
How is hypotension/normotension defined?
How is mean arterial pressure (MAP) measured and
reported?
2.2. Literature review: selection criteria
Table 1 summarizes the entries that were introduced in
PubMed, Scopus and LIMO.
No limits were set for language, year, field. A manual search
for articles containing information on the operation time,
blood loss, transfusion, and orthognathic surgery was
performed in the following journals until 1976:
• British Journal of Oral and Maxillofacial Surgery
• International Journal of Oral and Maxillofacial Surgery
• Journal of Craniofacial Surgery
• Journal of Cranio-Maxillo-Facial Surgery
• Journal of Oral and Maxillofacial Surgery
• Oral & Maxillofacial Surgery Clinics of North America
• Oral and Maxillofacial Surgery
• Oral Surgery, Oral Medicine, Oral Pathology, Oral
Radiology, and Endodontics
• Plastic and Reconstructive Surgery
• Revue de Stomatologie et de Chirurgie Maxillo-faciale
An additional manual search was done to retrieve theses
on the subject of blood transfusion in orthognathic
surgery. Two theses were included [6,7], both in German.
2.2.1. Inclusion criteria
The criterion for retention for further processing was a
clear allocation of the operation time AND/OR blood
loss AND/OR transfusion to one of following operations:
1. SSO (advancement or set-back)
2. Le Fort I osteotomy one-piece without
concomitant procedures
3. Le Fort I osteotomy multisegmental or with
additional operations
4. Bimaxillary surgery without concomitant procedures
5. Bimaxillary surgery with simultaneous other
procedures (e.g., iliac bone graft, cranial bone graft,
genioplasty, liposuction, septoplasty, rhinoplasty
inferior turbinate reduction, and removal of third
molars).
These operations needed to be the predominant operation
if a certain group was correlated with the duration of the
operation and/or blood loss. If the predominancy of any
of these types of operations could not be established, the
group was discarded for further analysis.
2.2.2. Exclusion criteria
Exclusion criteria were craniofacial surgery in children;
articles where blood loss, operation time, or transfusion
could not be clearly attributed to one of the categories
mentioned; case reports on syndromes; and case reports
or reviews on major postoperative hemorrhagic events.
In addition, retrospective reports on large numbers of
Stomatology Edu Journal
Table 1. Summary of the entries that were introduced in PubMed,
Scopus and LIMO.
Entry
Blood loss and
orthognathic
Transfusion and
orthognathic
Operative time and
orthognathic
Hypotension and
orthognathic
Blood transfusion and
orthognathic surgery
Medline Scopus Limo
121 6 80
62 6 26
35 10 157
50 5 18
62 2 25
procedures were often not suitable for inclusion because
they did not separate the different categories needed. No
minimal number of patients was required to be included.
3. Results
3.1. Search results
In total, 51 papers and 2 theses were retained that
contained valuable subgroups with information. Both
retrospective and prospective studies were accepted,
no matter if the procedures were done in normotension,
mild hypotension, controlled hypotension, or any other
tension reported (see Appendix 1)
3.2. Meta-analysis or systematic review
Meta-analysis was not the approach used because there
was no control group for comparison. Control groups
were used to compare the effect of different medications
that influence the depth of controlled hypotension or to
compare the effect of certain antifibrinolytic agents such
as aprotinin, aminocaproic acid, and tranexamic acid to
stabilise clot formation. Because the levels of reduced
blood loss of these measures are considered below clinical
relevance compared to the type of surgical procedure
selected [8], aggregation of data is needed. Therefore, the
following differences have been neglected:
• different methods to realise anaesthesia (gas, iv
medication);
• different methods to reach mild, moderate, or deep
hypotension; and
• different or no use of antifibrinolytic agents.
BLOODLOSS AND TRANSFUSION NEED IN ORTHOGNATHIC SURGERY:
REVIEW OF LITERATURE
3.2.1. Aggregation of data
Many different descriptions of procedures and
techniques needed to be united in a concise and
coherent way, leading to a number of categories per
label, allowing focus on the targeted questions. These
characteristics were defined as seen in Appendix 2.
3.3. Measurement of blood loss
To compare blood loss in comparable surgical procedures
(BSSO, Le Fort I, bimaxillary surgery), measurement of
blood loss has to be comparable. In that respect, we found
that in 22 out of 51 papers, the method of measuring
estimated blood loss was missing [9-30].
In 18 out of 51 papers, the estimated blood loss was
measured by deducting the volume of saline used from
the total volume in the suction unit and by weighing
the sponges [31-48], others 10 mL [43].
In 6 out of 51 papers, losses in sponges were not included
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