Key words
Wound tension - skin tension - wound assessment - wound healing
Schlüsselwörter
Wundspannung - Hautspannung - Wundbeurteilung - Wundheilung
Introduction
Halsted’s 7 principles of surgery have been established for over 120 years
[1], but objective data on wound tension are
limited. Subjective assessment of wound tension by experienced surgeons remains the
gold standard in small animal surgery, as there are no established methods for
objective quantification or reference values for wound tension to guide the
surgeon’s decision whether to close the wound primarily without any
tension-relieving procedures [2]. The detrimental
impact of high wound tension on wound healing has led to the development of a
variety of tension relieving techniques [3].
Although there is a negative correlation between wound tension and microcirculation
in the skin adjacent to the suture line [4] no
guidelines exist for determining the maximum safe tension for primary wound closure
in dogs or cats.
Human studies have shown a wide range of acceptable wound tensions, making it
difficult to establish practical reference ranges [5]
[6]. Additionally, there is a lack of
reliable and practical devices for objective quantification of wound tension,
especially for routine clinical use [7]. In
consequence, every inexperienced surgeon must go through a learning curve aimed at
acquiring the manual skill to reliably assess wound tension during surgery and gain
the necessary experience if a wound is suitable for primary closure based on
subjective assessment of wound tension. Individual wound assessment gets complicated
due to various factors that influence wound properties. These factors encompass
various aspects, including the specific location of the wound and anatomical
characteristics such as the elasticity of the skin, the quantity of subcutaneous
tissue, and the hydration of the skin. Consequently, the individual nature of wound
tension may lead to inadequate decision-making when relying solely on subjective
evaluation, thus highlighting the need for a more objective approach.
To address these limitations, we developed a wound tensiometer for easy and fast
intraoperative measurement of wound tension in dogs. This study aimed to compare the
subjective assessment of wound tension between inexperienced and experienced
surgeons and to establish thresholds for maximal wound tension in medium- and
large-breed dogs. Because many surgeons tend to include wound size in their
decision-making process for wound closure [7], we
also examined the correlation between wound size and wound tension, hypothesizing
that no predictable correlation exists.
Materials and methods
The tensiometer
The tensiometer used in this study consists of 2 distinct components ([Fig. 1]). First, a commercially available
spring scale is employed, along with a specially designed hand instrument made
of medical-grade steel, resembling an oversized towel clamp. The spring scale
serves to connect the 2 branches of the tensiometer, counteracting the force
exerted at the tip of the jaws during temporary wound adaptation. This
arrangement reflects the force required to apposition the wound edges, which is
equivalent to the measured wound tension. To ensure a secure and reliable grip
on the wound edges without slippage, 2 small spheres measuring 1.5 mm in
diameter are strategically placed distal to the pointed tips of the instrument
([Fig. 1b]). Additionally, considering
the lever action of the tensiometer’s branches, the spring scale is
adjusted to reflect the true force value at the tip of the instrument.
Furthermore, the instrument is designed to be foldable, enabling a reduction in
the space required during sterilization. Standard sterilization methods such as
steam, gas, or plasma, can be employed for the sterilization process. These
sterilization methods have undergone rigorous validation using a variety of
instruments, and their efficacy has been presumed based on the specific
materials used for the tensiometer.
Fig. 1
The wound tensiometer. a The complete wound tensiometer.
b Close-up view of the tip, showing 2 adjustment spheres for
limiting the insertion depth of the tip into the skin. c The
tension screw for applying tension to the device. d Foldable side
arm designed to hold the spring scale. Source: F. Lackmann.
Abb.
1
Das Wundtensiometer. a Das vollständige
Wundtensiometer. b Vergrößerte Ansicht des
vorderen Endes mit zwei Kugeln zur Begrenzung der Eindringtiefe der
Spitze in die Haut. c Die Spannschraube zur Anwendung der
Spannung am Gerät. d Klappbarer Seitenarm zur Befestigung
der Federskala. Quelle: F. Lackmann.
The process for measuring wound tension involves the following steps ([Fig. 2]):
Fig. 2
Practical application of the tensiometer for measuring skin wound
tension. a The tips of the tensiometer are secured onto the
edges of the skin wound, approximately 2 to 3 mm away from the
skin margins. Typically, the tensiometer is positioned at the widest
point of the wound where maximum tension is anticipated. Partially close
the skin wound and ensure that the spring scale is already under
tension. b Rotate the tension dial clockwise (indicated by the
red arrow) to increase the force exerted on the spring scale, gradually
bringing the skin wound edges closer together. c Continue
shortening the suture by adjusting the tension dial until the wound
edges are in proper alignment. d Take the measurement (indicated
by the red arrow) of the final wound tension in Newton. Source: F.
Lackmann.
Abb. 2
Praktische Anwendung des Tensiometers zur
Messung der Hautwundspannung. a Die Spitzen des Tensiometers
werden in die Wundränder der Haut eingehakt, etwa 2 bis
3 mm von den Hauträndern entfernt. In der Regel wird das
Tensiometer an der breitesten Stelle der Wunde platziert, wo die
Wundspannung voraussichtlich am höchsten ist. Schließen
Sie die Hautwunde teilweise und stellen Sie sicher, dass die Federskala
bereits unter Spannung steht. b Drehen Sie das Spannrad im
Uhrzeigersinn (roter Pfeil), um die Kraft auf die Federskala zu
erhöhen und die Hautwunde allmählich zu
schließen. c Fahren Sie fort, die Naht zu
verkürzen, indem Sie das Spannrad drehen, bis die
Wundränder aneinander liegen. d Lesen Sie die
endgültige Wundspannung in Newton ab (siehe Pfeil). Quelle: F.
Lackmann.
-
Begin by inserting the tips of the tensiometer into the skin wound edges,
positioning them approximately 2 to 3 mm from the skin margins.
For optimal results, place the tensiometer at the widest point of the
wound, where the maximum tension is anticipated. Partially close the
skin wound, ensuring that the spring scale is already taut.
-
Gradually increase the force applied to the spring scale by rotating the
tension dial clockwise (indicated by the red arrow). This action
progressively brings the skin wound closer together.
-
Continue shortening of the suture by turning the tension screw until the
wound edges are appropriately aligned.
-
Obtain the final measurement of wound tension (indicated by the red
arrow) in Newton (N).
Wound tension assessment
An initial experimental setup for ex vivo quantification of skin wound tension
involved 8 medium to large breed dogs (BW 20 to 40 kg), including 1
Labrador Retriever, 1 Bernese Mountain Dog, 1 German Shepherd Dog, 1 Golden
Retriever, 1 Boxer and 3 mixed breeds with normal body condition score (BCS).
These dogs were euthanized for reasons unrelated to the study. The cadavers were
stored at –20°C and double-sealed in plastic bags to prevent
desiccation, with storage durations varying up to 6 months. The cadavers were
free of visible skin diseases and skin wounds on the trunk. For final
processing, the bodies were thawed at room temperature for 48 hours.
In each of the 8 dogs, a total of 4 full-thickness skin wounds were randomly
created, with 2 located in the lateral thoracic region and 2 in the lateral
abdominal region ([Fig. 3]). The wounds were
generated by resecting elliptical skin areas of varying sizes, ranging from
4×10 cm to 15×25 cm (width x length). The
longitudinal axis of the wound was aligned parallel to the tension lines, as
reported by Deroy et al. [8]. The selection of
random dimensions aimed to achieve a heterogeneous distribution of resulting
wound sizes. Following the immediate creation of the wounds, 5 experienced
surgeons (all ECVS diplomates and/or professors of small animal surgery)
and 5 inexperienced surgeons assessed wound tension by palpation. They were
blinded to any quantification of wound tension using the tensiometer. After
evaluation, all surgeons were asked to assess the possibility of primary wound
closure without any tension-relieving procedures. Subsequently, wound tension
was objectively quantified using the tensiometer by averaging 3 consecutive
measurements. Care was taken to ensure that no manipulation other than of the
wound edges occurred between the subjective assessment by the surgeon and the
subsequent objective quantification of the skin wound.
Fig. 3
Schematic representation of randomly created full-thickness skin
wounds along the thoracic and abdominal body wall. Wound size
(indicated by blue arrows) was measured as the length between the wound
edges at the widest point of the wound, perpendicular to the
longitudinal axis of the wound. Two wounds were created on each side of
the body. Source: F. Lackmann.
▶Abb. 3
Schematische
Darstellung der nach dem Zufallsprinzip angelegten Hautwunden
entlang der thorakalen und abdominalen Körperwand. Die
Wundgröße (durch blaue Pfeile gekennzeichnet) wurde als
die Länge zwischen den Wundrändern an der breitesten
Stelle der Wunde gemessen, senkrecht zur Längsachse der Wunde.
Es wurden jeweils 2 Wunden pro Körperseite angelegt. Quelle: F.
Lackmann.
The second experimental setup aimed to replicate wound tension and associated
wound size as realistically as possible. This setup exclusively utilized
cadavers within 1 hour post-mortem. Eleven cadavers of medium to large
breed dogs (BW 20 to 40 kg) were included, comprising 1 Labrador
retriever, 1 Boxer, 2 Australian shepherds, 2 German shepherds, 1 Munsterlander,
1 Hanover hound, 1 English Bulldog and 2 mixed breeds with normal BCS. These
dogs had been euthanized for reasons unrelated to the study, with no apparent or
reported involvement of their integument. To prevent interference between
adjacent wounds, only 1 elliptical full-thickness skin wound was created per
side of the body, 1 in the thoracic and 1 in the abdominal region ([Fig. 4]). Similar to the first experiment, the
wounds were aligned according to the skin tension lines reported by Deroy et al.
[8]. Initially, the wounds measured
5×10 cm (width x length). After preparing the skin wounds, a
randomly selected experienced surgeon evaluated wound tension independently by
palpation and determined whether the wound could be closed directly by
apposition without employing tension-relieving procedures. The quantification of
wound tension followed the procedure described in Experiment 1, with the surgeon
blinded to both the reading and the exact size of the skin wound. Subsequently,
the wound size was increased by 1 centimetre, and the surgeon conducted a
subjective evaluation of the tension, followed by quantification of the skin
tension and size. The size of the wound was defined as the distance between the
wound edges at the widest point of the wound while maintaining a consistent
height measurement. This procedure was repeated until the surgeon deemed the
wound unsuitable for direct appositional closure, and a final recording of wound
tension and wound size was taken.
Fig. 4
Schematic representation of the location and gradual enlargement of
the thoracic wounds in trial 2. The abdominal wound was always
positioned on the contralateral body wall, to prevent any mechanical
interaction between the 2 wounds. After the randomly selected
experienced surgeon subjectively evaluated the skin wound tension and an
independent observer quantified the wound size using the tensiometer,
approximately 1 cm of skin was removed from both wound edges to
enlarge the wound. Subsequent subjective evaluation and objective
quantification of wound tension were performed again. This process was
repeated until the surgeon subjectively assessed that primary closure of
the wound without additional relaxation techniques was unfeasible.
Source: F. Lackmann.
Abb. 4
Schematische Darstellung der Lage
und graduellen Vergrößerung der Thoraxwunden in
Versuch 2. Die abdominale Wunde befand sich stets an der
kontralateralen Körperwand, um jegliche mechanische Interaktion
zwischen den beiden Wunden auszuschließen. Nachdem der
zufällig ausgewählte erfahrene Chirurg die
Hautwundspannung subjektiv bewertet und ein unabhängiger
Beobachter die Wundgröße mit dem Tensiometer
quantifiziert hatte, wurde etwa 1 cm Haut von beiden
Wundrändern entfernt, um die Wunde zu
vergrößern. Anschließend erfolgte erneut eine
subjektive Bewertung und objektive Quantifizierung der Wundspannung.
Dieser Vorgang wurde wiederholt, bis der Chirurg bei subjektiver
Einschätzung den primären Verschluss der Wunde ohne
zusätzliche Entspannungstechniken als nicht durchführbar
einschätzte. Quelle: F. Lackmann.
Data Analysis
Descriptive statistics were conducted using commercial software (MedCalc v.
20.218, MedCalc Software Ltd, Belgium). The normal distribution assumption was
assessed using the D’Agostino-Pearson omnibus test. Since the data did
not follow a normal distribution, the median with an associated interquartile
range of 75% was reported. Group-wise comparisons were performed using
the Mann-Whitney U Test for unpaired data and the Wilcoxon test for paired data.
Correlation analysis was conducted using Spearman’s rank correlation
coefficient. A significance level of α≤0.05 was used for all
tests.
Results
The repeatability of the tensiometer results was high, with a maximum deviation
during the 3 consecutive measurements of 0.2 N. The accuracy of the
tensiometer was verified on a test stand with calibrated weights. A 500 g
weight was attached to the tensiometer and if the spring scale did not read
4.9 N, the spring tension was calibrated to that value.
In the initial trial, inexperienced surgeons recommended direct wound apposition up
to a maximum wound tension of 6.4 N (IQR: 5.4–7.1) ([Fig. 5]; [Table
1]). They deemed wound tension to be excessive for direct appositional
skin closure when it reached or exceeded 2.8 N (IQR: 2.65–4.35).
Fig. 5
Relation between the subjective decision on wound closure and the
objective quantification of skin wound tension by 5 inexperienced
surgeons in 32 randomly created skin wounds (n=152). The
blue dots represent the wound assessments in which the inexperienced
surgeons proposed simple direct skin closure because wound tension was
subjectively perceived to be low enough (n=91). The orange dots
represent the wounds where wound tension was perceived to be too high to
simply close the wound without using a tension-relieving procedure
(n=61). The yellow highlighted dots represent the maximal wound
tension measured for each surgeon for the wounds with simple wound closure.
Source: F. Lackmann.
▶Abb. 5
Verhältnis zwischen
der subjektiven Entscheidung über den Wundverschluss und der
objektiven Quantifizierung der Hautwundspannung von 5 unerfahrenen
Chirurgen bei 32 zufällig angelegten Hautwunden
(n=152). Die blauen Punkte stellen die Wundbewertungen dar,
bei denen die unerfahrenen Chirurgen einen einfachen direkten Hautverschluss
vorschlugen, da die Wundspannung subjektiv als niedrig genug empfunden wurde
(n=91). Die orangefarbenen Punkte stellen die Wunden dar, bei denen
die Wundspannung als zu hoch empfunden wurde, um die Wunde einfach zu
schließen, ohne dass ein spannungsentlastendes Verfahren empfohlen
wurde (n=61). Die gelb markierten Punkte stellen die maximale
Wundspannung für jeden Chirurgen dar, bei der ein einfache
Wundverschluss empfohlen wurde. Quelle: F. Lackmann.
Table 1 Median maximal and minimal wound tension recordings
for experiments 1 and 2.
▶Tab. 1 Maximale und minimale
Wundspannungsmesswerte aus Experiment 1 und 2.
|
Max Novice surgeons
|
Min Novice surgeons
|
Max Experienced surgeons
|
Min Experienced surgeons
|
|
Experiment 1
|
6.4
|
2.8
|
5.4
|
6.0
|
|
Experiment 2 Thoracic
|
–
|
–
|
4.4
|
6.0
|
|
Experiment 2 Abddominal
|
–
|
–
|
4.0
|
5.6
|
|
Experiment 2 Pooled data
|
–
|
–
|
4.2
|
6.0
|
On the other hand, experienced surgeons suggested direct wound apposition up to a
maximum wound tension of 5.4 N (IQR: 5.15–5.6) ([Fig. 6]; [Table
1]), while they considered wound tension to be too high for direct
appositional skin closure when the wound tension was equal to or greater than
6.0 N (IQR: 5.45–6.0). The difference between the lower and upper
cut-off values was found to be significant in the inexperienced group
(p=0.0422), but not in the experienced surgeons (p=0.2528).
Fig. 6
Relation between the subjective decision on wound closure and the
objective quantification of skin wound tension by 5 experienced surgeons
(in 32 randomly created skin wounds n=152). The blue dots
represent the wound assessments in which the experienced surgeons proposed
simple direct skin closure because wound tension was subjectively perceived
to be low enough (n=101). The orange dots represent the wounds where
wound tension was perceived to be too high to simply close the wound without
using a tension-relieving procedure (n=51). The yellow highlighted
dots represent the maximal wound tension measured for each surgeon for the
wounds with simple wound closure. Source: F. Lackmann.
▶Abb.
6
Verhältnis zwischen der subjektiven Entscheidung über
den Wundverschluss und der objektiven Quantifizierung der
Hautwundspannung von 5 erfahrenen Chirurgen bei 32 zufällig
angelegten Hautwunden (n=152). Die blauen Punkte stellen die
Wundbewertungen dar, bei denen die erfahrenen Chirurgen einen einfachen
direkten Hautverschluss vorschlugen, weil die Wundspannung subjektiv als
niedrig genug empfunden wurde (n=101). Die orangefarbenen Punkte
stellen die Wunden dar, bei denen die Wundspannung als zu hoch empfunden
wurde, um die Wunde einfach zu schließen, ohne dass ein
spannungsentlastendes Verfahren empfohlen wurde (n=51). Die gelb
markierten Punkte stellen die maximale Wundspannung für jeden
Chirurgen dar, bei der ein einfacher Wundverschluss empfohlen wurde. Quelle:
F. Lackmann.
The comparison of data between inexperienced surgeons and experienced surgeons
revealed no significant difference in maximum wound tension and minimum wound
tension (p=0.0670, p=0.0517). However, considering that the minimum
wound tension in the inexperienced surgeon group was lower than the maximum wound
tension, the reference range for wound tension guiding the decision of whether or
not to close the wound directly was established based on the data from the
experienced surgeons only. According to this reference range, direct wound closure
would be recommended for wound tensions up to 5.4 N, while it would be
rejected for wound tensions exceeding 6.0 N.
When facing gradually enlarged skin wounds in fresh cadavers (experiment 2),
experienced surgeons recommended direct wound closure for both thoracic and
abdominal wounds up to a wound tension of 4.4 N (IQR: 3.325–4.0) and
4.0 N (IQR: 3.85–4.95), respectively, which was not significantly
different from each other (p=0.8945). Combining the data, direct wound
closure was advised up to a maximal wound tension of 4.2 N (IQR:
3.8–5.0). The minimal wound tension for thoracic and abdominal wounds in
which wound apposition was declined was 6.0 N (IQR: 5.55–6.35) and
5.6 N (IQR: 5.1–6.71), respectively, not being significantly
different (p=0.4469). Pooling the data, direct wound closure was not
recommended with a minimal wound tension of≥6.0 N (IQR:
5.4–6.4). Thus, the reference range for wound tension associated with direct
wound apposition, derived from experiment 2, was determined to be between
4.2 N and 6.0 N ([Fig. 7]; [Table 1]).
Fig. 7
Relation between the subjective decision on wound closure and objective
quantification of skin wound tension in gradually enlarged abdominal and
thoracic skin wounds, with constant wound height and gradual widening of
the wound, by 5 experienced surgeons in 11 dogs (n=22). The
blue dots represent the wound assessments with the maximal wound tension in
which the experienced surgeons proposed simple direct skin closure because
tension was subjectively perceived to be low enough (n=22). The
orange dots represent the wounds where wound tension was perceived to be too
high to simply close the wound, without using a tension-relieving procedure
(n=22). Source: F. Lackmann.
▶Abb. 7
Verhältnis zwischen der subjektiven Entscheidung über
den Wundverschluss und der objektiven Quantifizierung der
Hautwundspannung von 5 erfahrenen Chirurgen bei allmählich
vergrößerten abdominalen und thorakalen Hautwunden bei
konstanter Wundhöhe und gradueller Verbreiterung der Wunde
(n=22) an 11 verschiedenen Hunden. Die blauen Punkte stellen
die Wundbewertungen mit den maximalen Wundspannungen dar, bei denen die
erfahrenen Chirurgen einen einfachen direkten Hautverschluss vorschlugen, da
die Wundspannung subjektiv als niedrig genug empfunden wurde (n=22).
Die orangefarbenen Punkte stellen die Wunden dar, bei denen die Wundspannung
als zu hoch empfunden wurde, um die Wunde einfach zu schließen, ohne
dass ein spannungsentlastendes Verfahren angewandt wurde (n=22).
Quelle: F. Lackmann.
Experiment 2 also showed a strong correlation between wound size and wound tension
(Spearman’s coefficient of rank correlation=0,819; CI:
0,741–0,875; p<0.0001) ([Fig.
8]).
Fig. 8
Correlation of wound size and tension in 11 fresh cadavers with thoracic
and abdominal skin wounds with consistent wound height measurements
(n=153). There is a strong correlation between wound size
and wound tension (rho=0,819; CI: 0,741–0,875;
p<0.0001), but there is also a high variation in wound tension for
the same wound size. Source: F. Lackmann.
▶Abb. 8:
Korrelation von Wundgröße und Wundspannung bei 11
frischen Kadavern mit thorakalen und abdominalen Hautwunden bei
gleichbleibenden Wundhöhen (n=153). Es besteht eine
starke Korrelation zwischen Wundgröße und Wundspannung
(Rho=0,819; CI: 0,741–0,875; p<0,0001), aber es
besteht ebenso eine große Variation der Wundspannung bei gleicher
Wundgröße. Quelle: F. Lackmann.
Discussion
The objective quantification of wound tension in this ex vivo study of
“simple” skin wound closure revealed 2 main findings: (1)
inexperienced surgeons lack the ability to reliably assess wound tension, and (2)
experienced surgeons would close skin wounds with tensions ranging from 4.2 to
5.4 N, without employing any tension-relieving technique.
The inexperienced surgeons exhibited an inconsistent perception of wound tension,
as
indicated by their perceived upper threshold being below the lower threshold. This
lack of a reliable sense of wound tension undermines their decision-making process
when determining whether to directly close a wound. Factors such as the location and
dimensions of the wound may further contribute to this inconsistency. While wound
size shows a strong correlation with wound tension and may initially seem like a
suitable clinical parameter for estimating wound tension, the significant individual
variations in tension among wounds of the same size and location, as observed in
this study, demonstrate that size alone is not a reliable substitute for assessing
wound tension. Size alone does not consider the individual variations and
topographic differences in the elasticity and mobility of the skin and subcutaneous
tissue. Therefore, it cannot be used as a substitute for assessing wound tension
accurately. Relying primarily on the size of the wound to determine the type of skin
closure will inevitably lead to excessive tension in the wound.
The factors influencing wound dehiscence are likely multifactorial, and the precise
impact of excessive wound tension in this process remains unproven [9]. To date, there is a lack of clinical studies
demonstrating a clear correlation between wound tension and wound dehiscence.
However, it is well-documented that wound closure under high tension can result in
reduced local blood flow and increased scarring [4]
[10]. Based on clinical experience,
Halsted formulated his principles, which emphasized the importance of preventing
excessive wound tension. These principles have been widely adopted by generations
of
surgeons and are included in relevant surgical textbooks [3].
Traditional assessment of wound tension in surgery involves manual palpation and
traction of wound edges [11]. It necessitates
manual training and clinical experience to establish a correlation between
intraoperative perceived wound tension and postoperative wound healing issues
associated with excessive tension during closure. To mitigate this frustrating and
potentially harmful learning curve, this study aimed to develop a quantitative
assessment of wound tension in a standard clinical setting. The newly designed
tensiometer proved to be user-friendly, compatible with standard sterilization
procedures, and demonstrated high precision and reliability. Surgeons facing
uncertainty regarding wound tension during closure may find value in utilizing this
objective measurement method to aid their decision on whether to proceed with simple
wound closure. Using the maximum and minimum wound tensions recorded by the
experienced surgeons in this study as references, a wound tension of 4.0 to
5.4 N, measured at the widest part of the skin wound, perpendicular to the
tension lines, would lead an experienced surgeon to choose simple skin wound
apposition. With a cut-off value of 5.6 to 6.0 N for the lower range of
documented skin wound tension, at which experienced surgeons rejected simple
appositional skin wound closure, a tension between 5.4 and 6.0 N might still
be considered “safe” by an experienced surgeon. According to our
study results, simple skin wound closure in wounds with tensions exceeding
6 N is not recommended. With that in mind, we have provided an objective
means for inexperienced surgeons to acquire expert knowledge in the operating room
without the need for physical peer supervision. While descriptions and images can
provide inexperienced surgeons with numerous additional guidelines for performing
surgical procedures, the assessment of skin wound tension continues to be a task
that can only be conducted manually by experienced peers, requiring the physical
presence of an experienced surgeon scrubbed in. Again, it is important to note that
all our measurements have not yet undergone clinical validation. Instead, they serve
as references for inexperienced surgeons until they can develop the same level of
reliability as experienced surgeons in assessing skin wound tension.
The relatively large gap between the lower and upper cut-off values (4.0/5.4
to 6.0 N) in the group of experienced surgeons reflects, to some extent, the
subjectivity and individuality inherent in their manual estimation of wound tension.
However, it is also influenced by the specific experimental setup we employed. A
more extensive evaluation of a larger number of skin wounds with a finer
distribution of sizes would likely have resulted in a narrower estimate for the
“safe cut-off value” for simple skin wound closure as determined by
experienced surgeons. Additionally, including a greater number of surgeons would
have increased statistical power and potentially eliminated the type-II error
observed when comparing cut-off values between inexperienced and experienced
surgeons.
The lower cut-off value observed in the second cadaver study using fresh cadavers,
compared to the slightly higher cut-off in the previously frozen cadavers, cannot
be
solely explained by differences in “wound tension.” Wound tension,
as a physical phenomenon, remains constant across tissues, but factors such as
deformation and stiffness can vary significantly. Given the evident differences in
skin elasticity and mobility between fresh and “old” cadavers, the
surgeons’ subjective perception of “wound tension” may be
influenced by these artificial disparities. Therefore, we recommend adhering to the
cut-off values derived from fresh cadavers to ensure consistency and accuracy in
assessing wound tension.
The main limitation in applying the findings of this study to clinical practice lies
in the absence of clinical data regarding measures of skin wound tension, the type
of skin closure utilized, and wound healing outcomes. Various factors such as age,
breed, underlying diseases, location and origin of the skin wound, medication,
patient compliance, and owner compliance are likely to have additional influence
[9]. While this study provides valuable
guidance for inexperienced surgeons in making more informed decisions regarding skin
wound closure using the tensiometer, clinical studies are necessary to assess and
establish the relationship between the degree of wound tension and the incidence and
nature of postoperative wound healing complications. It is important to note that
just because an experienced surgeon determines that a wound can be safely closed
without tension-relieving procedures, it does not guarantee that the current wound
tension is optimal for uncomplicated wound healing. The provided reference values
serve as an indication of what experienced surgeons would recommend, but these
cut-off values need to be validated and further refined through the analysis of real
clinical cases with appropriate follow-up.
Incorporating the use of the tensiometer in clinical practice can also assist
surgeons in performing tension-relieving procedures. By conducting serial
measurements of skin wound tension, surgeons can determine if there has been a
satisfactory reduction in wound tension. Additionally, this device enables dynamic
assessment of wound tension, which is particularly valuable in areas where tension
levels are affected by limb positioning.
Conclusion for practice
Our study introduces a novel wound tensiometer for veterinary surgery, providing
reference values for skin wound tension that experienced surgeons would deem
appropriate for straightforward appositional skin closure. This tool serves as a
valuable resource for inexperienced surgeons, offering guidance during the process
of skin wound closure until they develop the expertise to independently assess wound
tension and select the appropriate skin closure method. Incorporating a tensiometer
into clinical practice may offer additional advantages for surgeons, particularly
in
tension-relieving procedures. Further in vivo studies and comparison of dehiscence
rates will follow to advance the practical application of the tensiometer.
