How to Suture: Simple Laceration Repair
This post may contain affiliate links, which means I get a commission if you decide to purchase through my links, at no cost to you. Please read affiliate disclosure for more information
Knowing how to suture is imperative for a nurse practitioner or any other provider, especially within Emergency, Urgent Care, and family practice settings. Your experience suturing during clinical will vary depending on your rotations, but unfortunately many NP students graduate without solid suture experience. Many job interviews will ask if you are comfortable suturing, and your answer could literally make or break the interview.
Hopefully this full breakdown of how to suture will help you be able to confidently know how to suture.
As a heads up, this article is long and full of helpful infographics, so to please feel free to use the Table of Contents to navigate this page if it helps!
Table of Contents
– Choosing your Suture Type
– Figure: Absorbable vs Nonabsorbable sutures
– Choosing your Suture Size
– Figure: Suture Size and Removal
– Choosing your Anesthetic
– Figure: Lido w/ Epi vs w/o
2. Anesthetize the Area
3. Irrigate the Laceration
4. Sterile Field
5. Suture (simple interrupted sutures)
– Figure: How to Suture
6. Dress the Wound
When to Suture?
Even if you know how to suture, don’t forget to recognize when to suture. Suturing is not always indicated. Sometimes there are other alternative wound closure options, and sometimes it is best to let the wound heal by itself (termed secondary intention).
Where is the Laceration?
The location of the laceration will help determine the need for sutures, as well as the size of sutures needed and when they should be removed. Sutures are commonly used for simple lacerations of the hands, feet, extremities, and face. Lacerations of the scalp are often better suited for closure with staples. Staples can also be used in areas where cosmetic results are not necessary, especially when the laceration is >5cm.
Depth of the Laceration
Superficial lacerations that do not extend through the epidermis often do not need to be sutured closed and will heal without difficulty with good cosmetic results. Additionally, some well-approximated lacerations that aren’t under areas of tension can be better closed with steri-strips or dermabond. Deeper gaping lacerations may need to have the subcutaneous tissue approximated with internal absorbable sutures first, then closed with non-absorbable sutures at the surface.
How Old is the Laceration?
The age of the laceration will have a major impact on your decision to suture. Clean, uninfected lacerations can be closed up to 18 hours following an injury. Facial wounds can be closed after the incident up to 24 hours, or even 48-72 hours in some cases with no risk factors for infection.
Mechanism of Injury
How the laceration occurred is also a very important part of the history in a patient with a laceration. This can cue you in on the need for X-rays to determine a foreign body or to rule out a possible fracture. A fracture with overlying open skin is considered an open fracture, and these should not be closed and are usually treated with at least one dose of IV antibiotics and Ortho consultation.
The mechanism of injury can also give you a better indication of the degree of contamination, although proper assessment of the wound should too. Seriously contaminated wounds require extensive irrigation and often prophylactic antibiotics with delayed closure.
Animal bites (including human bites), especially in non-cosmetic areas such as the hands or feet, should NOT be closed as these are at high risk for infection. However, in some instances, primary wound closure can be done such as with certain dog bites. If the patient has diabetes or venous stasis, delayed closure is even more highly recommended. Be sure to give rabies immunoglobulin and vaccine when bitten by strays or unvaccinated animals that cannot be quarantined.
Cat bites should be left open and treated with prophylactic antibiotics (usually Augmentin), and can be referred for delayed closure in 3 days if needed. However, cat bites on the face can be closed if within 24 hours prior to closure. Puncture wounds should not be closed.
Dog bites have also traditionally been recommended to treat with prophylactic antibiotics and refer for delayed closure. However, recent literature seems to support primary closure of many of these wounds as a reasonable alternative. Most dog bites on the face, trunk, and extremities can be sutured, as long as <12 hours old, or <24 hours for the face. Bites on the hands or feet should not be closed, but rather referred in 3 days for potential delayed closure and of course treated with antibiotics as above.
Similar to cat bites, human bites should never be initially closed unless on the face that is less than 24 hours old. These wounds also warrant prophylactic antibiotics.
Updating tetanus shots is necessary to prevent the patient from developing tetanus disease. Tetanus is a disease that can occur after contamination of a wound which causes painful muscle stiffness and spasms. In order to make sure the patient’s tetanus is up to date, you need to ask the patient when their last tetanus vaccination was. Many patients will not know.
Update Tetanus Vaccination if:
- Received < 3 doses in their lifetime
- Last dose > 10 years in clean and minor lacerations/ wounds
- Last dose > 5 years in contaminated/complex* wounds (see below)
Give tetanus immune globulin if:
- Less than 3 Tetanus vaccinations in past (or unknown) AND contaminated/complex* wounds
- HIV positive patients or those with severe immunocompetence
*Contaminated wounds are those contaminated with feces, soil, dirt, or saliva. Complex wounds include puncture wounds, avulsions, crush injuries, or burns.
|Clean Wound||Dirty** Wound|
|<3 Tdap* or unknown||Tdap||Tdap + TIg|
|>3 Tdap but LKD >10y||Tdap||Tdap|
|>3 Tdap but LKD >5y||None||Tdap|
*Tdap or Td (tetanus containing vaccination)
TIg = Tetanus Immune Globulin | LKD = Last Known Dose | UTD = Up To Date
**Dirty wounds are those contaminated with feces, soil, dirt, or saliva; puncture wounds, avulsions, crush injuries, or burns.
Perform Appropriate Wound Assessment
A good assessment of the laceration is also necessary. Be sure to assess their distal neurovascular status. Assess the tendon function in hand lacerations – make sure full ROM is maintained distal to the injury. Make sure no visible tendons are lacerated. Assure the wound does not appear infected or grossly contaminated. Observe for any signs of foreign bodies and ensure that bleeding is controlled. Measure the laceration’s length, width, and depth. These are all part of a good wound/laceration assessment and necessary for adequate documentation.
Laceration Documentation Example: “4x1x1 cm laceration noted to the right posterior proximal forearm. Wound appears clean with smooth edges and scant bleeding. There are no foreign bodies or debris noted. No tendons are visualized. Distal neurovascular status intact including pulse, cap refill, color, temperature, sensation, and ROM.”
How to Suture
So now we know it is appropriate to suture, we’ve updated the patient’s tetanus if needed, and we have done a proper assessment of the patient’s laceration. We can finally learn how to suture a laceration. In this article, I will be overviewing the most common suturing method, which is the simple interrupted suture, which is appropriate for most simple lacerations.
Before you’re able to suture, you will need to collect all of your equipment to irrigate, clean, anesthetize, suture, and dress the wound.
- Bottle of NS (50-100cc per cm) or an equivalent volume of tap water (One 250ml NS bottle usually sufficient)
- 30-60cc syringe
- 18g IV catheter (remove the needle)
- Absorbable pads or towels
- Kidney basin
- Splash guard
Suture Kit: (Often already collected and packaged)
- Sterile drapes / field
- Gauze (4×4)
- Needle Driver
- Tweezers or small toothed forceps
- 1 pair of clean gloves (for cleaning, irrigation, and anesthetizing)
- 1 pair of sterile gloves (for suturing)
Sutures: See below
- Lidocaine with or without Epinephrine
- 3-10cc syringe
- 25-30g needle
- Blunt needle
There are many different suture types, those that are either absorbable or nonabsorbable. Each suture type will change the suture’s properties including tensile strength, knot strength, elasticity, and whether or not they will absorb on their own.
Nonabsorbable sutures have been the standard for simple laceration repairs, and they are what I almost always use. These can be used anywhere and have good tensile strength, knot security, are easy to work with, and have minimal tissue reactivity (aside from silk). Nonabsorbable sutures include:
Nylon: High tensile strength, elastic, minimal tissue reactivity, low cost, requires 3-4 knot throws.
Polypropylene (Prolene): High tensile strength, low tissue reactivity, requires 4-5 knots. Can come in blue color which is helpful in the scalp or dark-skinned individuals
Polybutester (Novafil): Similar to above, but has greater elasticity so can be helpful if significant wound edema is expected
Silk: Not as strong, higher tissue reactivity, but still used for central lines, chest tubes, etc
Absorbable sutures used to only be used for deep sutures, and are still used for internal sutures with very deep lacerations. However, some advocate for its use in primary closure of percutaneous lacerations in adults and children using fast-absorbing gut sutures. This is especially useful in children who will fight against suture removal. Some common absorbable sutures are:
Chromic gut: retains tensile strength for 10-14 days, often used for oral mucosa, but has increased tissue reactivity for subcutaneous internal sutures.
Vicryl: Retains tensile strength 3-4 weeks, complete absorption in 60-90 days. Ideal choice for subcutaneous sutures.
Vicryl Rapide: Retains tensile strength 10-14 days, “falls off” in 7-10 days. Useful for under casts, can be used as an alternative to nonabsorbable sutures , but possible risk of infection and tracking vs nonabsorbable although was NOT statistically significant in research.
Absorbable vs Nonabsorbable?
While nonabsorbable are generally recommended for wound closure, a meta-analysis found equivalent cosmetic outcomes and no significant difference in wound infection or dehiscence, although follow-up was insufficient in several studies. Department culture will often dictate what you use. You will not gro wrong with nonabsorbable nylon interrupted sutures of the appropriate size.
The size of the sutures will determine how big the needle and thread are. Depending on the location, certain sizes are recommended. The larger the number, the smaller the size and lower the strength. 1-0 are the largest, and 10-0 are the smallest, but most simple laceration repairs will use anywhere between 3-0 to 6-0.
To choose your size, simply assess where the laceration is. See the table below for more information.
|Location||Suture Size||When to Remove|
|Scalp||4-0 or 5-0|
|Eyelid||6-0 or 7-0||5-7 days|
|Eyebrow||5-0 or 6-0||5-7 days|
|Oral Mucosa||5-0 (chromic gut)||NA|
|Arm||5-0, 4-0 near joint||7-10 days|
|Chest/Abdomen||4-0 or 5-0||12-14 days|
|Back||4-0 or 5-0||7-10 days|
Choosing the Anesthetic
To suture, you will need to numb the surrounding area as you will be sticking a needle in their skin multiple times. Your main decision will be whether or not to use the lidocaine with or without epinephrine.
Lidocaine is the go-to anesthetic for laceration repair. Max dose is 5mg/kg (max 300mg), which you won’t come close to with smaller basic lacerations. The 1% comes in at 10mg/mL, and the 2% is 20mg/mL. Lidocaine will begin working in 45-90 seconds, and will last for 30-90 minutes.
Lidocaine is usually injected via local infiltration. Enter the subcutaneous space from the inside of the wound, slowly making your way around the entire laceration circumference. Most basic lacerations will only require between 1-3cc of lidocaine.
Local infiltration will give the patient a “pinch and a burn” while injecting. One way to decrease pain is to mix 1cc of bicarb with 10cc of lidocaine. However, in adults the lidocaine injections are usually tolerable, so this may be more wasteful than helpful. Alternatively, frequent pinching of the skin has been found to decrease discomfort.
Lidocaine 1-2% with Epinephrine 1:100,000
Lidocaine with Epi is great for wounds that are bleeding or are more likely to bleed while suturing. These include highly vascular areas like the face. This is because the epinephrine causes local vasoconstriction. It also blanches the skin, which makes it easy to see where you’ve numbed after a few minutes. The addition of epinephrine also causes decreased systemic absorption, causing a longer duration of action of the lidocaine (~3 hours).
Traditionally Lido w/ Epi was avoided in areas like the fingers, nose, or ears as the worry is causing vasoconstriction and risking skin necrosis. However, the evidence is lacking so Uptodate basically says you can. However, it is still recommended to avoid injecting the digits with epinephrine-containing lidocaine in those with peripheral vascular disease.
Prepare the area with 1 or 2 absorbable pads and have clean gauze ready, as local infiltration will often cause mild bleeding of the wound as well as leakage of the anesthetic agent.
Clean the wound surface with an alcohol wipe (which will sting) or diluted betadine (1:10 iodine to NS solution). This is to briefly clean the area before injecting, as you likely have not irrigated the wound yet. Do not use betadine surgical scrub as this can be toxic to the wound.
Use a blunt needle to draw up your anesthetic into a 3cc or 5cc syringe. Replace the needle with a fresh 25-30g needle. Inject the dermal area just inside the edge of the wound, locally infiltrating the anesthetic. You should be able to see the surrounding skin “swell” up. Note that sometimes the anesthetic has a tendency to leak out the wound – catch this with your clean gauze. Remove the needle and inject it again, slowly making your way around the wound. Be sure to use the previously numbed tissue that you just injected. It won’t be fully numb yet, but it will be less painful for the patient with subsequent pokes.
For lacerations on the distal digits, a digital block will likely be the best choice, as there is usually not much space to infiltrate in these areas. These are also very sensitive, and local infiltration can be very uncomfortable for the patient.
Irrigation of a laceration is essential to prevent infection and clear any foreign bodies or debris. Cleaner wounds will need less irrigation, whereas more contaminated wounds will need more irrigation. Generally, it is acceptable to irrigate 50-100cc per cm of the laceration.
To irrigate, make sure your absorbable pads are in place as this can get the patient pretty wet.
Open a sterile NS bottle or alternatively use tap water, and fill a 30-60cc syringe. Attach an 18g catheter to the end of the syringe – this is to increase the pressure of the irrigation. Inject the water or saline into the wound with high pressure, catching any water with a kidney basin if possible. The use of a splash guard is helpful to prevent splashback.
Once cleaned, it is often easier to measure the dimensions of the wound.
Once the laceration has been anesthetized and irrigated, you can begin setting up your sterile field.
Maintaining a sterile environment is another important factor in preventing infection. However, it might not be as necessary as once thought when suturing a simple laceration. Multiple randomized control trials (RCTs) have found clean gloves did not have higher infection rates than sterile gloves. Nonetheless – sterile technique is still often recommended and is considered the “standard”.
Most suture kits will have sterile drapes within them. Open your suture kits in a sterile fashion. Drop your open sutures onto the kit or field in a sterile manner. Drop any other necessary equipment (gauze) if needed.
Clinical Tip: You can pour some sterile NS into small containers or the sterile kit itself onto the gauze. This is optional but I find it personally useful to have wet gauze when wiping away scant bleeding during the procedure.
Remove your clean gloves, wash your hands, and apply sterile gloves. Set up your sterile drapes – have the patient lift their arm or leg to assist you if needed. Some kits will have a sterile perforated drape to help focus your sterile field, which is optional. Once you are all set up, you can finally start suturing.
To begin suturing, you first need to decide which type of suture technique you are going to use. Most simple lacerations can be repaired with simple interrupted sutures. This is what I use 99% of the time in the Emergency Department.
Before placing sutures, make sure the bleeding has stopped, as continued bleeding after closure can lead to hematoma formation.
To perform the simple interrupted stitch, insert the needle at a 90° angle (side A). You should start about 5mm (0.5cm) from the edge of the laceration, 5mm deep, and come out 5mm on the other side of the wound. Facial lacerations require a finer touch and are recommended to be 2.5mm from edge, 2.5mm deep, and 2.5mm apart.
I usually place the first suture in the center of the laceration. You will often need 2 bites for the first stitch – one for each side of the wound, as the edges of the wounds are usually not well approximated. However, I find that often after the first stitch the other sutures can usually be achieved within one bite.
Clinical Tip: You can use toothed or untoothed forceps in your suture kit to help manipulate the skin – but I find this is usually unnecessary and leads to more local trauma to the wound.
Once you pull your needle through the other side (side B), pull the thread through until you leave a short tail on the original side. Place your needle driver in the middle, parallel to the wound. Wrap the long-tail side B around the needle driver with two loops for the first throw. Grab onto the short tail of Side A with the needle driver, pulling toward side B while simultaneously pulling the long-tail side B toward side A. Pull tight enough to approximate the skin but not too tight. This creates a square knot. Be sure to pull the knot to one side of the wound so that it is not overlying the laceration. Perform this same knot throw about 3-4 more times, except you only need to loop around the needle driver once instead of twice for subsequent throws in the same knot.
Clinical Tip: When tying the knots, be sure to do most of the pulling with the long-tail and your hand, as pulling too hard on the short-tail with the needle driver can elongate the tail and lead to wasted suture material. As far as number of knots, a good rule of thumb is to use the same amount of knot throws as the size of the sutures (3 knots for 3-0, 4 knots for 4-0, 5 knots for 5-0, etc).
When you have thrown the appropriate number of knots, use the scissors in your kit to cut both ends at approximately 5mm length.
For your next stitch, you can start working in either direction about 5mm away from the first (2.5mm on the face), or you can bisect each remaining side until the wound is closed.
Once the laceration is closed, the last step is to dress the wound. Apply bacitracin or Neosporin directly to the wound, and then apply a nonadherent dressing. I use a Telfa dressing covered by dry gauze, then wrapped with Kerlix. Other nonadherent dressings can be used as well (nonadherent sterile gauze), and even a simple bandaid can be used for small lacerations (works well for the face).
Providing excellent discharge instructions is imperative, as there is usually a good amount of necessary follow-up that needs to occur.
Tell the patient to leave the dressing in place for 24-48 hours, and can then be opened to air. The wound should be covered if possible contamination is expected (such as while at work). Nonabsorbable stitches can be cleaned gently with soap and water twice a day. Half-strength hydrogen peroxide can be used twice daily to prevent crusting over sutures, especially on the face. The patient can use an OTC antibiotic ointment or white petroleum ointment twice a day as well if desired, which can help prevent scar formation and promote healing. It is generally recommended to avoid submerging the wound in water until it is healed.
My Patient Discharge Instructions: Keep the wound clean and dry for 24-48 hours, then you can wash it gently twice a day with soap and water, but otherwise do not submerge wound in water. You may use Neosporin if desired to help prevent infection and scab formation. Please return for a wound check in 2-3 days if red/swollen/or if there is discharge from the wound, otherwise your sutures will need removed in X days. This can be done at your doctor’s office, an urgent care, or back here in the ED.
Always recommend a wound check in 2-3 days if the patient has any noticed redness, swelling, or discharge of the wound. Otherwise – they will need to follow-up when the sutures will need to be removed (which will depend on the location as stated above).
If the patient is high-risk for infection (Diabetes, on chemo, renal disease, etc) or if the wound was highly contaminated, a wound check in 2-3 days should be recommended regardless.
Prophylactic PO antibiotics can be given for contaminated wounds, animal or human bites, patients with vascular insufficiency, or immunocompromise.
That concludes how to suture! There are other suture methods, and there isn’t always a “one size fits all”. If you are still confused, there are plenty of videos on youtube which you can check out as well! Let me know if you have any questions below and I’ll try to answer them. For more in-depth reading, check out the Uptodate articles listed in the references below!
TextBooks: *Contains affiliate links*