An orthopaedic surgeon makes a modification to an operative approach for total knee
arthroplasty. After he has completed 25 cases, he stops and reviews his patient
outcomes. He publishes the data. What level of evidence is supplied by this type of
data?
A. II
B. IV
C. III
D. V
E. I
Case series that are non randomised and lack concurrent controls at best supply level
IV evidence only. To qualify for level I and II evidence a prospective randomised
controlled trial with appropriate blinding, control matching and power calculations is
needed.
Levels of evidence
The level of evidence refers to the study design used by investigators to minimise
bias.
Level of Source
evidence
I Evidence obtained from systematic review of all relevant randomised
controlled trials
II Evidence derived from at least one properly designed randomised
controlled trial
III Evidence derived from well designed pseudo-randomised controlled
trials (e.g. alternate allocation) or historical controls
IV Evidence derived from case series or case reports
V Panel or expert opinion
Many of the categories contain sub groups, detailed knowledge of these are not
required for MRCS Part A.
Theme: Use of suture materials and closure devices
A. Silk 3/0
B. Polyglactin 3/0
C. Polydioxanone 1/0
D. Stainless steel skin clips
E. Stainless steel wire 1/0
F. 6/0 Polypropylene
G. 3/0 Undyed polyglactin
,H. Polypropylene 3/0
Please select the most appropriate suture material for the situation described. Each
option may be used once, more than once or not at all.
2. Mass closure of abdominal wall following elective right hemicolectomy through
a midline incision.
Polydioxanone 1/0
PDS or polydioxanone is the ideal suture material. Non absorbable sutures have
higher incidence of incisional herniae.
3. Closure of the sternum following coronary artery bypass grafting.
Stainless steel wire 1/0
Stainless steel wire is typically used.
4. Application of vein patch to femoral artery following endarterectomy.
6/0 Polypropylene
Polypropylene is the suture of choice. Fine sutures are preferred.
Suture material
Suture materials
Agent Classification Durability Uses Special points
Silk Braided Theoretically Anchoring devices, Knots easily, poor
Biological permanent skin closure cosmesis
although
strength not
preserved
Catgut Braided 5-7 days Short term wound Poor cosmesis
Biological approximation Degrades rapidly
Not available in
UK
Chromic catgut Braided Up to 12 weeks Apposition of Unpredictable
Biological deeply sited tissues degradation
pattern
Not in use in UK
,Polydiaxonone Synthetic Up to 3 months Widespread Used in most
(PDS) Monofilament (longer with surgical surgical
thicker sutures) applications specialties (avoid
including visceral dyed form in
anastomoses, dermal closure)
dermal closure,
mass closure of
abdominal wall
Polyglycolic Braided Up to 6 weeks Most tissues can be It has good
acid (Vicryl, Synthetic apposed using handling
Dexon) polyglycolic acid properties, the
dyed form of this
suture should not
be used for skin
closure
Polypropylene Synthetic Permanent Widely used, agent Poor handling
(Prolene) Monofilament of choice for properties
vascular
anastomoses
Polyester Synthetic Permanent Its combination of It is more
(Ethibond) Braided permanency and expensive and has
braiding makes it considerable
useful for tissue drag
laparoscopic
surgery
Absorbable vs Non absorbable
Time taken to degrade absorbable materials varies
Usually by macrophages hydrolysing material
Consider absorbable sutures in situations where long term tissue apposition is
not required. In cardiac and vascular surgery non absorbable sutures are
usually used.
Suture size
The higher the index number the smaller the suture i.e. : 6/0 prolene is finer
than 1/0 prolene.
Finer sutures have less tensile strength. For example 6/0 prolene would not be
a suture suitable for abdominal mass closure but would be ideal for small
calibre distal arterial anastomoses.
Braided vs monofilament
Generally speaking braided sutures have better handling characteristics than non
braided. However, they are associated with higher bacterial counts. Braided materials
are unsuitable for use in vascular surgery as they are potentially thrombogenic.
Which of the following visceral anastomoses has the lowest risk of anastomotic leak?
You may assume that all are constructed in ideal circumstances.
, A. Stapled ileocolic anastomosis
B. Hand sewn anastomosis of the proximal ileum
C. Stapled colorectal anastomosis defunctioned with loop ileostomy
D. Stapled colorectal anastomosis defunctioned with loop colostomy
E. Hand sewn oesophagojejunal anastomosis
Rectal and oesophageal surgery have some the highest risk of anastomotic leakage,
rates following anterior resection are quoted to be up to 10%. Small bowel
anastomoses are the most technically forgiving. Factors increasing the risk of
anastamotic leakage include previous irradiation, sepsis, malnutrition, poor blood
supply and poor technique.
The defunctioning of rectal anastomoses may reduce the clinical impact of
anastomotic leak and make it amenable to percutaneous drainage, but does not
necessarily reduce the incidence of leaks themselves.
Anastomoses
A wide variety of anastomoses are constructed in surgical practice. Essentially
the term refers to the restoration of luminal continuity. As such they are a
feature of both abdominal and vascular surgery.
Visceral anastomoses
For an anastomosis to heal three criteria need to be fulfilled:
Adequate blood supply
Mucosal apposition
Minimal tension
When these are compromise the anastomosis may dehisce (leak). Even in the best
surgical hands some anastomoses are more prone to dehiscence than others.
Oesophageal and rectal anastomoses are more prone to leakage and reported leak rates
following oesophageal and rectal surgery can be as high as 20%. This figure includes
radiological leaks and those with a clinically significant leak will be of a lower order
of magnitude. As a rule small bowel anastomoses heal most reliably.
The decision as to how best to achieve mucosal apposition is one for each surgeon.
Some will prefer the use of stapling devices as they are quicker to use, others will
prefer to perform a sutured anastomosis. The attention to surgical technique is more
important than the method chosen and a poorly constructed stapled anastomosis in
thickened tissue is far more prone to leakage than a hand sewn anastomosis in the
arthroplasty. After he has completed 25 cases, he stops and reviews his patient
outcomes. He publishes the data. What level of evidence is supplied by this type of
data?
A. II
B. IV
C. III
D. V
E. I
Case series that are non randomised and lack concurrent controls at best supply level
IV evidence only. To qualify for level I and II evidence a prospective randomised
controlled trial with appropriate blinding, control matching and power calculations is
needed.
Levels of evidence
The level of evidence refers to the study design used by investigators to minimise
bias.
Level of Source
evidence
I Evidence obtained from systematic review of all relevant randomised
controlled trials
II Evidence derived from at least one properly designed randomised
controlled trial
III Evidence derived from well designed pseudo-randomised controlled
trials (e.g. alternate allocation) or historical controls
IV Evidence derived from case series or case reports
V Panel or expert opinion
Many of the categories contain sub groups, detailed knowledge of these are not
required for MRCS Part A.
Theme: Use of suture materials and closure devices
A. Silk 3/0
B. Polyglactin 3/0
C. Polydioxanone 1/0
D. Stainless steel skin clips
E. Stainless steel wire 1/0
F. 6/0 Polypropylene
G. 3/0 Undyed polyglactin
,H. Polypropylene 3/0
Please select the most appropriate suture material for the situation described. Each
option may be used once, more than once or not at all.
2. Mass closure of abdominal wall following elective right hemicolectomy through
a midline incision.
Polydioxanone 1/0
PDS or polydioxanone is the ideal suture material. Non absorbable sutures have
higher incidence of incisional herniae.
3. Closure of the sternum following coronary artery bypass grafting.
Stainless steel wire 1/0
Stainless steel wire is typically used.
4. Application of vein patch to femoral artery following endarterectomy.
6/0 Polypropylene
Polypropylene is the suture of choice. Fine sutures are preferred.
Suture material
Suture materials
Agent Classification Durability Uses Special points
Silk Braided Theoretically Anchoring devices, Knots easily, poor
Biological permanent skin closure cosmesis
although
strength not
preserved
Catgut Braided 5-7 days Short term wound Poor cosmesis
Biological approximation Degrades rapidly
Not available in
UK
Chromic catgut Braided Up to 12 weeks Apposition of Unpredictable
Biological deeply sited tissues degradation
pattern
Not in use in UK
,Polydiaxonone Synthetic Up to 3 months Widespread Used in most
(PDS) Monofilament (longer with surgical surgical
thicker sutures) applications specialties (avoid
including visceral dyed form in
anastomoses, dermal closure)
dermal closure,
mass closure of
abdominal wall
Polyglycolic Braided Up to 6 weeks Most tissues can be It has good
acid (Vicryl, Synthetic apposed using handling
Dexon) polyglycolic acid properties, the
dyed form of this
suture should not
be used for skin
closure
Polypropylene Synthetic Permanent Widely used, agent Poor handling
(Prolene) Monofilament of choice for properties
vascular
anastomoses
Polyester Synthetic Permanent Its combination of It is more
(Ethibond) Braided permanency and expensive and has
braiding makes it considerable
useful for tissue drag
laparoscopic
surgery
Absorbable vs Non absorbable
Time taken to degrade absorbable materials varies
Usually by macrophages hydrolysing material
Consider absorbable sutures in situations where long term tissue apposition is
not required. In cardiac and vascular surgery non absorbable sutures are
usually used.
Suture size
The higher the index number the smaller the suture i.e. : 6/0 prolene is finer
than 1/0 prolene.
Finer sutures have less tensile strength. For example 6/0 prolene would not be
a suture suitable for abdominal mass closure but would be ideal for small
calibre distal arterial anastomoses.
Braided vs monofilament
Generally speaking braided sutures have better handling characteristics than non
braided. However, they are associated with higher bacterial counts. Braided materials
are unsuitable for use in vascular surgery as they are potentially thrombogenic.
Which of the following visceral anastomoses has the lowest risk of anastomotic leak?
You may assume that all are constructed in ideal circumstances.
, A. Stapled ileocolic anastomosis
B. Hand sewn anastomosis of the proximal ileum
C. Stapled colorectal anastomosis defunctioned with loop ileostomy
D. Stapled colorectal anastomosis defunctioned with loop colostomy
E. Hand sewn oesophagojejunal anastomosis
Rectal and oesophageal surgery have some the highest risk of anastomotic leakage,
rates following anterior resection are quoted to be up to 10%. Small bowel
anastomoses are the most technically forgiving. Factors increasing the risk of
anastamotic leakage include previous irradiation, sepsis, malnutrition, poor blood
supply and poor technique.
The defunctioning of rectal anastomoses may reduce the clinical impact of
anastomotic leak and make it amenable to percutaneous drainage, but does not
necessarily reduce the incidence of leaks themselves.
Anastomoses
A wide variety of anastomoses are constructed in surgical practice. Essentially
the term refers to the restoration of luminal continuity. As such they are a
feature of both abdominal and vascular surgery.
Visceral anastomoses
For an anastomosis to heal three criteria need to be fulfilled:
Adequate blood supply
Mucosal apposition
Minimal tension
When these are compromise the anastomosis may dehisce (leak). Even in the best
surgical hands some anastomoses are more prone to dehiscence than others.
Oesophageal and rectal anastomoses are more prone to leakage and reported leak rates
following oesophageal and rectal surgery can be as high as 20%. This figure includes
radiological leaks and those with a clinically significant leak will be of a lower order
of magnitude. As a rule small bowel anastomoses heal most reliably.
The decision as to how best to achieve mucosal apposition is one for each surgeon.
Some will prefer the use of stapling devices as they are quicker to use, others will
prefer to perform a sutured anastomosis. The attention to surgical technique is more
important than the method chosen and a poorly constructed stapled anastomosis in
thickened tissue is far more prone to leakage than a hand sewn anastomosis in the
