Musculoskeletal problems and injuries - part 8 pot

Slight undercutting of the wound edges facilitates slight eversion of the wound edge.. Deep sutures provide most of the strength of the repair,and skin sutures approximate the skin margi

Phase Three: Maturation (Remodeling) Phase

The wound continues to undergo remodeling for 18 to 24 months, ing which time collagen synthesis continues and retraction occurs.Normally during this time the scar becomes softer and less conspicu-ous The prominent color of the scar gradually fades, resulting in a hueconsistent with the surrounding skin Aberrations of the maturationprocess can result in an unsightly scar such as a keloid Such scars aredue to a combination of inherited tendencies and extrinsic factors ofthe wound Proper technique in wound care and repair minimizes theextrinsic contribution to keloid formation If it is necessary to revise anunsightly scar, the ideal delay is 18 months or more after the initialrepair

dur-Anesthesia

Under most circumstances it is preferable to anesthetize the woundprior to preparation for closure Before applying anesthesia, thewound is inspected using a slow, gentle, aseptic technique to ascertainthe extent of injury including an assessment of the neurovascular supply At this time a decision is made to refer the patient if the com-plexity of the wound warrants consultation

Topical Agents

When appropriate, topical anesthesia is ideal, as pain can be relievedwithout causing more discomfort or anxiety Small lacerations may beclosed without additional medications

PAC (Pontocaine/Adrenaline/Cocaine) and

TAC (Tetracaine/Adrenaline/Cocaine)

Pontocaine or tetracaine 2%/aqueous epinephrine (adrenaline)

be prepared in a 100-mL volume by mixing 25 mL of 2% tetracaine, 50

mL of 1:1000 aqueous epinephrine, 11.8 g of cocaine, and sterile normalsaline to a volume of 100 mL

Placing a saturated pledget over the wound for 5 to 15 minutes oftenprovides adequate local anesthesia Blanching of the skin beyond themargin of the wound allows an estimation of adequate anesthesia.Further anesthesia may be applied by injection if necessary

that of TAC, but it takes nearly twice as long to anesthetize the skin(30 minutes) The same guideline of skin blanching applies to the use

of Emla

Ethyl Chloride

A highly volatile fluid, ethyl chloride comes in commercially pared glass bottles with a sprayer lid This fluid can be sprayed ontothe skin surface by inverting the bottle and pressing the lid The flam-mable fluid chills the skin rapidly The agent may be applied until skinfrosting occurs It provides brief anesthesia, allowing immediateplacement of a needle without causing additional pain

pre-Injectable Agents

Lidocaine

Lidocaine produces moderate duration of anesthesia (about 1–2hours) when used in a 1% or 2% solution When mixed with1:100,000 aqueous epinephrine, the anesthetic effect is prolonged(2–6 hours), and there is a local vasoconstrictive effect Any anes-thetic mixed with epinephrine should be used with caution on fingers,toes, ears, nose, or the penis to avoid risk of ischemia and subsequentnecrosis Occasional toxicity occurs with lidocaine, but most reac-tions are due to inadvertent intravascular injection Manifestations oftoxicity include tinnitus, numbness, confusion, and rarely progression

to coma True allergic reactions are unusual

It is possible to reduce the discomfort of lidocaine injection bybuffering the solution with the addition of sterile sodium bicarbon-

bicar-bonate (44 mEq/50 mL) is less painful to inject but provides the samelevel of anesthesia as the unbuffered solution It is also possible tobuffer other injectable agents including those with epinephrine.However, epinephrine is unstable at a pH above 5.5 and is commer-cially prepared in solutions below that pH Therefore, any bufferedlocal anesthetic with epinephrine must be used within a short time

provides additional reduction of the pain of injection Buffering also appears to increase the antibacterial properties of anesthetic

Additional Agents

Mepivacaine (Carbocaine) produces longer anesthesia than lidocaine(about 45–90 minutes) It is not used with epinephrine Reactions aresimilar to those seen with lidocaine Procaine (Novocain) works quicklybut has a short duration (usually less than 30–45 minutes) It has a widesafety margin and may be used with epinephrine Bupivacaine(Marcaine) is the longest-acting local anesthetic (approximately 6–8hours) It is often used for nerve blocks or may be mixed with lidocainefor problems that take longer to repair It is also useful for injecting into

a wound to provide postprocedural pain relief It may be mixed withepinephrine and is available in 0.25%, 0.50%, and 0.75% solutions

Diphenhydramine

Diphenhydramine (Benadryl) may also be used as an injectable

an efficacy similar to that of lidocaine Diphenhydramine may be pared in a 0.5% solution by mixing a 1-mL vial of 50 mg diphenhy-dramine with 9 mL of saline This solution is useful when a patientclaims an allergy to all injectable anesthetics

pre-Anesthetic Methods

Infiltration Blocks

Infiltration blocks are useful for most laceration repairs The wound isinfiltrated by multiple injections into the skin and subcutaneous tis-sue Using a long needle and a fan technique decreases the number ofinjection sites and therefore decreases the pain to the patient Using a27-gauge or smaller needle to inject through the open wound marginalso minimizes the patient’s discomfort, as does moving from an anes-thetized area slowly toward the unanesthetized tissue

Field Blocks

Field blocks result in similar pain control but may distort the woundmargin less and are useful where accurate wound approximation is nec-essary (e.g., the vermillion border) The area around the wound isinjected in a series of wheals completely around the wound, therebyblocking the cutaneous nerve supply to the laceration This technique ismore time-consuming but produces longer-lasting anesthesia Anotheroption to reduce the initial pain of the injection is to produce a smallwheal using buffered sterile water and then injecting the anestheticthrough the wheal The buffered water has a brief anesthetic action

between the digits at the metacarpophalangeal joint on each side ofthe digit (Fig 11.2) Mouth and tongue lacerations are repairableusing dental blocks It is useful to receive practical instruction in suchblocks from a dental colleague.

Sedation

provides excellent protocols for sedative use by family physicians.Under adequate observation sedative agents can help the doctor deal

Injection sites and infiltration zone for digital nerve block

Injection sites, common digital nerve blocks

Fig 11.2 Digital nerve block.

with difficult patients For all agents described herein, it is imperativethat there be appropriate monitoring and that adequate resuscitationequipment be readily available The welfare of the patient is of primeconcern, and such medications should not be used solely for theprovider’s convenience.

Ketamine

Ketamine is a phencyclidine derivative It provides a dissociative stateresulting in a trancelike condition and may provide amnesia for theprocedure Ketamine can be administered by many routes, but themost practical for laceration repair is the oral method It usuallyresults in significant analgesia without hypotension, decreased heartrate, or decreased respiratory drive The use of proper monitoring andthe availability of resuscitation equipment is mandatory Oral keta-mine can be prepared by adding 2.5 mL of ketamine hydrochlorideinjection (100 mg/mL) to 7.5 mL of flavored syrup It is then given at

a dose of 10 mg/kg Sedation occurs over 20 to 45 minutes after tion The most common side effects include nystagmus, random

Midazolam (Versed)

Midazolam is a benzodiazepine with typical class effects of hypnosis,amnesia, and anxiety reduction It is readily absorbed and has a shortelimination half-life It may be given as a single dose via the nasal,oral, rectal, or parenteral route The rectal route is useful when thepatient is combative A cooperative patient prefers oral or nasaladministration (oral dose 0.5 mg/kg; nasal dose 0.25 mg/kg, by nasaldrops) Injectable midazolam is used to make a solution that may begiven orally or nasally The drug should be made into a 5 mg/mL solu-tion For oral use it may be added to punch or apple juice to improvethe taste The maximum dose for children by any route is 8 mg.For rectal administration, a 6-French (F) feeding tube is attached to

an angiocath connected to a 5-mL syringe The lubricated catheter isthen inserted into the rectum and the drug injected followed by asyringe full of air to propel the medication into the rectum The tube isthen withdrawn and the patient’s buttocks are held together for approx-imately 1 minute The dose is 0.45 mg/kg by this route The medicationmay begin to work as soon as 10 minutes after administration Sideeffects may be delayed, so the patient should be observed for at least anhour as the duration of a single dose lasts about an hour Some burningcan occur when the nasal route is used Inconsolable agitation may

Fentanyl is a powerful synthetic opioid that produces rapid, ing sedation and analgesia Like other opioids, its effects arereversible, and it has limited cardiovascular effects Although it can begiven in many forms, oral transmucosal fentanyl citrate (OTFC) isavailable commercially in a lollipop (Fentanyl Oralet) This drug,commonly used as an preanesthetic medication, is available in threedosage forms (200, 300, and 400 mg) The dose for adults is 5 mg/kg

short-last-to a maximum of 400 mg regardless of weight Pediatric dosagesbegin at 5 mg/kg to a maximum of 15 mg/kg or 400 mg (whichever isless) Children weighing less than 15 kg should not receive fentanyl.OTFC effects are apparent 5 to 10 minutes after sucking the Oralet.The maximum effect is usually achieved about 30 minutes after use,but effects may persist for several hours Side effects are common butusually minor About half of patients develop transient pruritus, 15%notice dizziness, and at least one third develop vomiting The most

Oversedation or respiratory depression responds to naloxone

Nitrous Oxide

Nitrous oxide is a rapid-acting anesthetic that works within 3 to 5

Commercial equipment is available to deliver a mixture of nitrous

occasional emesis The efficacy of nitrous oxide is known to be able Although some patients object to the use of the mask, manypatients prefer using a specially designed self-administration mask.Nitrous oxide can cause expansion of gas-filled body pockets, and forthat reason it should not be used in patients with head injuries, pneu-mothoraces, bowel obstructions, or middle ear effusions

vari-Wound Preparation

Proper preparation of a wound can improve the success of cally acceptable healing The wound should be closed as soon as pos-sible, although most lacerations heal well if closed within 24 hours

aestheti-after the injury After anesthesia, proper cleansing should be plished by wiping, scrubbing, and irrigating with normal saline using

accom-a laccom-arge syringe with or without accom-a 22-gaccom-auge needle, which producesenough velocity to clean most wounds Antiseptic soaps such as hexa-chlorophene (pHisoHex), chlorhexidine gluconate (Hibiclens), orpovidone-iodine (Betadine) can also be used, but one should be awarethat all of these cleansing agents with the exception of normal salinewill delay wound healing to some extent by destroying fibroblasts andleukocytes as well as bacteria Sterile scrub brushes may be useful forcleaning grossly contaminated lesions

After washing and irrigation, the area is draped with sterile towels

to create a clean field The wound is then explored using sterile nique to confirm the depth of injury, ascertain whether injury tounderlying tissue has occurred, rule out the presence of any foreignbody, and determine the adequacy of anesthesia After examination,debridement is performed if necessary

tech-Debridement is the process of converting an irregular dirty wound

to a clean one with smooth edges Wound margins that are crushed,mangled, or devitalized are excised unless it is unwise to do so Tissue

in areas such as the lip or eyelid should be removed with extreme tion It is pointless to increase the deformity when a somewhat imper-fect scar can provide a more functional result If a considerableamount of tissue has been crushed, initial removal of all the damagedtissue may result in undesirable function (such as would occur if theskin over a joint were removed) Such injuries should be closedloosely using subcutaneous absorbable sutures The scar can berevised later if necessary

cau-The initial incision is made with a scalpel followed by excision with

a pair of sharp tissue scissors The edges should be perpendicular to theskin surface or even slightly undercut to facilitate eversion of the skinmargins (Fig 11.3) In hairy areas incisions should parallel the hairshafts to minimize the likelihood of hairless areas around the healedwound (Fig 11.4)

After debridement the skin edges are held together to see if it

is possible to approximate them with minimal tension Generally, it isnecessary to undermine the skin to achieve greater mobility of the sur-face by releasing some of the subcutaneous skin attachments that pre-vent the skin from sliding (Fig 11.5) This step takes place in thesubcutaneous layer and can be done with a scalpel or scissors Thewound is then undermined circumferentially about 4 to 5 mm fromthe edge of the margin The undermining should be equal across thewound and widest where the skin needs to move the most, usually thecenter of the cut

Hemostasis can be accomplished most easily by simple pressure onthe wound site for 5 to 10 minutes If pressure is unsuccessful, bleed-ers may be carefully cauterized or ligated Cautery or ligation can hin-der healing if large amounts of tissue are damaged Small vessels can

be controlled with absorbable suture if necessary, but large arterial

Fig 11.3 Slight undercutting of the wound edges facilitates

slight eversion of the wound edge

Fig 11.4 Parallel debridement in a hairy area avoids damaging

hair follicles

bleeders may need to be controlled with permanent ligature if it ispossible to do so without compromising the distal circulation If ooz-ing persists, the wound is closed with a drain (e.g., a sterile rubberband or Penrose drain) left in the wound several days An overlyingpressure dressing minimizes bleeding Advancing the drain everyother day permits healing with minimal hematoma formation.

Wound Closure

Suture options are listed in Table 11.1 Absorbable materials are ually broken down and absorbed by tissue; nonabsorbable sutures aremade from chemicals that are encapsulated by the body and thus iso-lated from tissue Monofilament sutures are less irritating to tissue butare more difficult to handle and require more knots than braidedsutures Stitches placed through the epidermis are done with nonab-sorbable materials to minimize the tissue reactivity that occurs withabsorbable stitches Reverse cutting needles in a three-eighths or one-half circle design are available in various sizes for each type of suture

grad-A well-closed wound has three characteristics: the margins areapproximated without tension, the tissue layers are accurately aligned,and dead space is eliminated Deep stitches are placed in layers thathold the suture, such as the fat–fascial junction or the derma–fat

Fig 11.5 Undermining the subdermal layer facilitates closure.

junction A buried knot technique is the preferred method for placingdeep sutures Deep sutures provide most of the strength of the repair,and skin sutures approximate the skin margins and improve the cos-metic result (Fig 11.6).

Suture Techniques19–21

Simple Interrupted Stitch

A simple interrupted stitch is placed by passing the needle through theskin surface at right angles, placing the suture as wide as it is deep.The goal is to place sutures that slightly evert the edge of the wound(Fig 11.7) This maneuver produces a slightly raised scar that recedesduring the remodeling stage of healing and leaves a smooth scar Theopposite margin is approximated using a mirror image of the firstplacement Following the natural radius of the curved needle placesthe suture in such a way as to evert the wound margin It can be mod-ified to correctly approximate the margins when the wound edges are

everted margins By reversing the usual approach and taking a stitchthat is wider at the top than at the base, the wound can be inverted,

Deep tissue

Subcutaneous tissue Dermis Epidermis

Fig 11.6 Layer closure showing sutures in the epidermis, at the

dermal–epidermal junction, and at the dermal–fat junction

improving the cosmetic appearance (Fig 11.9) A useful general rule

is that the entrance and exit points should be 2 mm from the margin

open-loop knot (Fig 11.10) avoids placing the suture under excessivetension and facilitates removal of the stitch The first throw of the knot

Fig 11.7 Simple interrupted suture with placement to facilitatewound eversion

Fig 11.8 Placement of suture in an asymmetric wound.

with two loops (“surgeon’s knot”) is placed with just enough tension

to approximate the wound margin The second throw, a single loop, istied, leaving a little space so no additional tension is placed on the firstloop Subsequent throws can be tightened snugly without increasingtension on the wound edge Pulling all the knots to the same side of

Fig 11.9 Suture placement in a wound with everted edges.

Fig 11.10 Model of skin showing surgeon’s knot.

Vertical or Horizontal Mattress Suture

The vertical mattress suture promotes eversion and is useful where thicklayers are encountered or tension exists Two techniques may be used.The classic method first places the deep stitch and closes with the super-

plac-ing the shallow stitch first, pullplac-ing up on the suture (tentplac-ing the skin),and then placing the deeper stitch Horizontal mattress sutures also havethe advantage of needing fewer knots to cover the same area

Intracuticular Running Suture

The intracuticular running suture, utilizing a nonabsorbable suture,can be used where there is minimal skin tension It results in minimalscarring without suture marks Controlled tissue apposition is difficultwith this method, but it is a popular technique because of the cosmeticresult The suture ends do not need to be tied but can be taped in placeunder slight tension (Fig 11.12)

Three-Point Mattress Suture

The three-point or corner stitch is used to minimize the possibility ofvascular necrosis of the tip of a V-shaped wound The needle is inserted

Fig 11.11 Vertical mattress suture.

into the skin of the wound edge on one side of the wound opposite theflap near the apex of the wound (Fig 11.13A,B) The suture is placed

at the mid-dermis level, brought across the wound, and placed versely at the same level through the apex of the flap It is then broughtacross the wound and returned at the same level on the opposite side ofthe V parallel to the point of entry The suture is then tied, drawing thetip of the wound into position without compromising the blood supply(Fig 11.13C) This method can also be used for stellate injuries wheremultiple tips can be approximated in purse-string fashion

trans-Running or Continuous Stitch

The running stitch is useful in situations where speed is important(e.g., a field emergency) because individual knots do not have to be

Fig 11.12 Intracuticular running stitch.