Abdominal wall and hernias

6


Abdominal wall and hernias





GENERAL ISSUES IN HERNIA SURGERY




1. Definition: A hernia is an abnormal protrusion of a viscus (Latin: internal organ) through its containing wall. Abdominal wall hernias are very common, especially in the groin (inguinal hernias) and umbilical area.


2. Diagnosis:



3. Indications to treat: Most hernias are operated on to ensure they do not enlarge, become uncomfortable, and to avoid the risk of strangulation. Reserve non-operative management for asymptomatic direct inguinal hernias, particularly in elderly, inactive or terminally ill patients and those who will not consent. The few who do not have an operation are best left without a truss, which is uncomfortable and difficult to manage.


4. Repair: There are three steps to a hernia repair:



5. Select the approach (open or laparoscopic): This depends on the hernia site, your surgical expertise, operating facilities, the patient’s anatomy and wishes. Laparoscopic repair requires different surgical skills, may be more expensive for the hospital than an open repair and cannot be undertaken under local anaesthetic.


6. Consent: Ensure the patient has given full consent to the operation and understands the circumstances under which it will be performed. Provide full information on discharge arrangements.


7. Suture the repair with a non-absorbable monofilament suture on a curved, round-bodied needle, polyamide (nylon) and polypropylene being the most popular. Remember the following:



8. Prosthetic mesh in hernia repair: If you use prosthetic mesh for the repair, give a prophylactic dose of antibiotic at induction. Always administer this in operations for strangulated hernia as the wound may be contaminated.


    Prosthetic mesh is an integral part of almost all hernia repairs as it often makes hernia surgery quicker and easier and reduces recurrence rates. There are many materials available, with several factors influencing choice:



image Strength/stiffness results not only from the intrinsic strength of the mesh, often related to the density of prosthetic material, but also from the resulting in-growth of fibrosis, which is greater with smaller pore sizes.


image Flexibility/elasticity: meshes should be flexible enough to conform to the abdominal wall movements on a long-term basis. It is increasingly apparent that current polypropylene meshes may be unnecessarily strong, resulting in pain and the sensation of stiffness when compared with lighter-weight open-weave or compound meshes (e.g. Vypro, Ethicon).


image Size and shape: all prostheses shrink as part of the process of scar maturation. Therefore allow a minimum overlap of the hernial defect by the mesh of 2–3 cm for initial fixation and long-term coverage. For laparoscopic ventral hernia repair, favour a 5-cm overlap. Various preformed meshes are now available for some hernia sites.


image Expense often limits the use of newer, composite meshes.


image Adhesion formation remains a problem, particularly with intraperitoneal implantation. Two-sided meshes, with one side engendering tissue ingrowth, the other inhibiting it (e.g. DualMesh, Gore, Proceed, Ethicon), reduce this risk.


image Infection: systemic prophylactic antibiotics have been shown to reduce the risk of wound infection.


9. Local anaesthesia is suitable for many groin hernia repairs and some other hernias. Young adults may not tolerate it alone and may require the addition of sedation. There are economic benefits, particularly for day-case surgery and in the elderly. Its use carries its own risks and the following general considerations apply:



10. Close the skin with sutures, clips, staples or adhesive strips. Continuous, absorbable subcuticular stitches provide a very neat result and avoid the discomfort and cost of suture removal.


11. Provide adequate postoperative analgesia. Inject local anaesthetic into the wound. Prescribe preoperative analgesics such as IV paracetamol and regular postoperative oral medication such as non-steroidal anti-inflammatories or co-codamol for 2 days.


12. Wound complications:



13. Hernia recurrence is related to technical failure, including a missed hernial sac and inadequate placement or sizing of the mesh.



INGUINAL HERNIA




Appraise




1. Most inguinal hernias are repaired.


2. Repair techniques: There are several open and laparoscopic techniques described to repair an inguinal hernia:



image The Lichtenstein mesh repair, developed by Irving Lichtenstein (1920–2000) of Los Angeles, in 1984; in 1989 he reported no recurrences in 1000 patients after 1–5 years. It is the most popular open technique, relatively easy to master and has a low recurrence rate Other open techniques repair the posterior wall of the inguinal canal by suturing the conjoint tendon to the inguinal ligament (Bassini repair) or by overlapping the transversalis fascia (Shouldice repair).


image Through a laparoscopic approach a synthetic mesh can be placed in the pre-peritoneal space from the midline medially to a point close to the level of the anterior superior iliac spine laterally, thus covering the whole extent of the inguinal canal including the internal ring and the area medial to the inferior epigastric vessels where direct hernias originate, as well as covering the internal opening of the femoral canal. The pre-peritoneal space can be reached either via a total extra-peritoneal (TEP) approach which should not involve entry into the peritoneal cavity, or via a transabdominal preperitoneal (TAPP) approach. For inguinal hernia repairs the TEP requires more surgical experience, but is considered safer as the peritoneum is not breached.


3. Selecting the correct approach to repair an inguinal hernia.



image Familiarize yourself with all techniques and adapt them according to the patient’s anatomy and wishes, rather than be compromised by lack of surgical expertise or equipment. The two approaches (open and laparoscopic) require very different surgical skills.


image The laparoscopic approach has slightly less postoperative pain, a faster return to work, a lower incidence of chronic groin pain and fewer wound complications. Long-term recurrence rates are similar for both methods. Laparoscopic repair costs more and carries a very small risk of serious injury to the intestine or major blood vessels, especially if the TAPP approach is adopted.


image The open operation has the advantage of being feasible under local anaesthesia. It is also cheaper and simpler to learn, and is currently recommended by NICE as the procedure of choice for primary, unilateral inguinal hernia in the UK. Consider especially women with primary unilateral inguinal hernias for open surgery.


image Repair a recurrent inguinal hernia through unscarred tissue: that is, if an open repair has recurred consider a laparoscopic approach, but if a laparoscopic repair has recurred consider an open approach.


image Bilateral inguinal hernia repairs are usually repaired laparoscopically as the operation is quicker. When repaired openly at the same time, the results are slightly inferior to separate repairs.


image For obese patients laparoscopic inguinal hernia repair is often easier.


image Undertake open repairs of large indirect inguinoscrotal hernias and urgent operations for hernias which may have strangulated.


image Avoid a laparoscopic approach if there has been previous lower abdominal surgery as a clear pre-peritoneal plane is difficult to find. Avoid it following previous open prostatectomy or procedures for urinary incontinence, but previous appendicectomy does not usually preclude it. A TAPP repair may be difficult or even hazardous if there are intraperitoneal adhesions following previous lower abdominal surgery.


image Select an open approach if there is an increased risk of bleeding such as anticoagulant therapy (even if was stopped preoperatively) or anti-platelet therapy such as clopidogrel, since bleeding can be more difficult to control than during the open operation.



Inspect




1. The diagnosis of groin swellings is notoriously difficult. Experienced as well as inexperienced surgeons make frequent mistakes. Do not accept the diagnosis of the referring doctor, but take a fresh history and carry out a complete examination. Is there another possible cause for the patient’s symptoms apart from the hernia? If a clear history of a reducible intermittent lump in the groin is accompanied by a negative examination, a hernia will be found on exploration; if in doubt, consider herniography.


2. Palpation is not the only or even the most important method of examination. Look with the patient standing and again with the patient supine. If you see a lump, ask yourself ‘Where is it?’ If it is reducible, where does it first reappear on coughing or straining? A cough impulse may be absent, especially over a femoral hernia in which a small sac is covered by much fatty extra-peritoneal tissue. Conversely, a cough impulse is present over Malgaigne’s (Parisian surgeon 1806–1856) bulging, or a saphena varix.


3. Always examine the scrotum and its contents in male patients. If there is a swelling, ask yourself the fundamental question ‘Can I get above it?’ Occasionally you discover undescended testes; deal with them at the same procedure.


4. Finally, examine the other hernial orifices.




OPEN MESH INGUINAL HERNIA REPAIR (Lichtenstein Repair)




Access




1. Start the incision a finger’s breadth above the palpable pubic tubercle within the skin crease which is often present (as opposed to parallel to the inguinal ligament) and extend this to two-thirds of the way to the anterior superior iliac spine. Incise the fascia to expose the external oblique aponeurosis, ligating and dividing two or three large veins that cross the line of the incision. Avoid cutting into the hernial sac and spermatic cord at the medial end of the incision.


2. Expose the glistening fibres of the external oblique aponeurosis and identify the external inguinal ring, which confirms the line of the inguinal canal.


3. With a scalpel split the external oblique aponeurosis in the line of the fibres. Enlarge the split medially and laterally by pushing the half-closed blades of the scissors in the line of the fibres. At the medial end of the split you open the external inguinal ring. Ensure that you do so. Do not allow curved blades of scissors to skirt around the crura of the ring. Preserve the ilioinguinal nerve, lying under the external oblique, to minimize the risk of postoperative numbness and pain.


4. Apply artery forceps to the edges of the aponeurosis and gently elevate each side. As you evert the upper leaf, look for the arching lower border of internal oblique muscle, with the cord below it. As you evert the lower leaf, sweep loose tissue from the deep surface of the inguinal ligament.



Assess (Fig. 6.1)







1. Start to mobilize the cord by incising, just above and lateral to the public tubercle, the ‘mesentery’ of fascia and fibres of cremasteric muscle that extends downwards from the medial part of the conjoint tendon to envelop the cord. Deepen this small incision behind the cord, drawing the latter downwards while passing the index finger from below against the pubic tubercle, to develop a plane to encircle the cord and apply a hernia ring.


2. Now dislocate the cord laterally and downwards by incising the coverings along lines just above and below it. This exposes a direct hernia, which can be freed from the cord.


3. Carefully divide the fibres of cremaster just distal to the internal ring, ensuring haemostasis.


4. Even though a direct hernia is evident, examine the cord. Normally it is about the thickness of a pencil. It is markedly distended by an unreduced, sometimes adherent or sliding, hernia. A thickened sac results from a longstanding indirect hernia. Cord lipomata produce thickening, as does an encysted hydrocele of the cord (in females a hydrocele of the canal of Nuck). To exclude an indirect sac, open the spermatic fascia covering the cord and identify the edge of the peritoneum deep to the internal ring.


5. Identify the lower arching fibres of the internal oblique muscle, becoming tendinous at the conjoint tendon, and examine the posterior wall below this. A direct hernia may be a large bulge, a diffuse weakness of the whole posterior wall or, less often, a funicular hernia through a small localized defect (Ogilvie’s hernia).


6. If you have any concern that a femoral hernia may be present, incise the transversalis fascia to expose the upper aspect of the femoral canal. If a femoral sac is present, deal with it via a High approach repair (Lothiesen procedure, see later).


7. The cremasteric vessels pass medially from the inferior epigastric vessels adjacent to the cord. If the internal ring is enlarged it may be necessary to carefully identify, isolate, ligate and then divide the cremasteric vessels to facilitate a snug repair at the internal ring. If they are injured more medially, ligate them proximally and distally to the damage.



Hernia sac



Indirect sac



1. With the left thumb in front, gently stretch the previously mobilized cord over the left index finger, which is placed behind the cord. Make a short split with a knife, in the line of the cord, through the cremasteric and internal spermatic fascial layers. Continue the split proximally to the internal ring using scissors, first with their blades on the flat, separating fascia from deeper layers, then splitting the fascia.


2. Look for the sac. A white curved edge may be seen if the hernial sac is small (Fig. 6.1); if it is large it will be obvious as the fascial layers are separated. Using the point of the scalpel, gently incise the fibres crossing the fundus or the side edges of the sac. Unless it is very adherent it will then be possible to peel the sac out of the cord with the aid of a few further strokes of the blade. The sac is then dissected back to the level of the abdominal peritoneum, using a combination of wiping with a gauze swab and snipping firm attachments with scissors. Keep the dissection close to the sac and avoid damaging other structures in the cord.


3. Pick up the sac with two artery forceps and open it between the forceps with a scissors. Note any contents of the sac and return them to the peritoneal cavity. Adherent omentum may be freed, or ligated and excised. Be sure this is not part of a sliding hernia (see below).


4. While the empty sac is held vertically by means of the artery forceps, transfix its neck with a polyglactin (Vicryl) suture. Tie the ends of the suture-ligature into a half hitch, completely encircle the neck of the sac and tie a triple-throw knot to ligate the neck of the sac. If contents tend to bulge into the sac, gently hold them back using non-toothed dissecting forceps, sliding them out as the ligature is tightened.


5. Do not let your assistant cut the ends of the ligature. First excise the sac 1 cm distal to the ligature. Examine the cut end to ensure that only sac is seen, it does not bleed and the suture is secure, then cut the ligature yourself. The stump of the sac should retract through the internal ring.


6. Alternatively, fully mobilize and simply invert the sac. It need not be ligated for this.


7. If the margins of the internal ring have been stretched by the indirect hernia, narrow the gap in the posterior wall using a non-absorbable suture to approximate the attenuated margins of the transversalis fascia medial to the cord.


8. If there are large extra-peritoneal lipomata, carefully isolate, ligate and excise them but do not try to dissect out all the fatty tissue.



Large indirect sac



1. Complete hernias, or scrotal funicular hernias, have no distal edge to the sac as seen at the level of the pubic tubercle. Attempts to dissect out the whole sac cause the scrotal part of the sac and the testis to be drawn into the wound, increasing the risk of haematoma or ischaemic orchitis.


2. Purposefully divide the sac straight across within the inguinal canal. Isolate the proximal portion up to the internal ring, and leave the distal portion open. In this way the dissection is kept to a minimum.


3. If the sac is adherent, open it in front and place artery forceps at intervals round the inside as markers. Lift up two forceps, stretch the portion of sac between them, separate the sac from the cord and cut it distal to the forceps. Take the next two forceps and repeat the manoeuvre. Continue in this manner until the proximal circumference of the sac is completely sectioned, with the edges still held in the forceps.


4. After stripping the proximal part of the sac to the inguinal ring, transfix and ligate the neck.


5. Leave the distal part of the sac open.



Sliding indirect sac



1. In some hernias, retroperitoneal structures slide down to form part of the sac wall, chiefly the sigmoid colon, bladder or caecum. Always be on the look-out for sliding hernia.


2. You discover the sliding component when you attempt to empty and free the sac.


3. If the sac is intact, do not open it. If the sac has been opened, mark the fringe of peritoneum on the viscus with artery forceps and close the sac. Ensure that closure is complete.


4. Make sure that neither the organ nor its blood supply was damaged before the true situation was recognized. If the bladder was damaged, repair the wall and remember to insert an indwelling urethral catheter at the end of the operation.


5. Fully mobilize the entire hernia sac and sliding viscus from the cord and replace it in the abdomen. If the sac is inguinoscrotal, divide and close it below the sliding viscus and return it to the abdomen.




Combined direct and indirect sac






Action




1. The mesh should have overall dimensions of 11 cm × 6 cm. To accommodate this, separate the external oblique aponeurosis from the deeper layers superiorly and medially and from the muscular part of internal oblique laterally to create an adequate pocket to receive the mesh.


2. Prepare the polypropylene mesh as indicated in Figure 6.2A. The lower medial corner is slightly rounded, the upper medial corner rather more so. The mesh is then incised from its lateral margin, placing the cut one-third of the distance from the lower edge. The cut extends for approximately half the length of the mesh, depending upon the size of the patient; it may need to be extended when the mesh is in place. In small patients the upper edge may need to be trimmed slightly.



3. Place the mesh in its final position (Fig. 6.2B). Lift the cord and bring the narrow lower tail through under it, below the internal ring. Then tuck the lateral end under the external oblique; the lower edge of the mesh now lies along the inguinal ligament. Now insert the upper two-thirds of the mesh so that it lies under the external oblique aponeurosis superiorly and medially, ensuring that there is a good overlap on the rectus sheath medially. Tuck the wide upper tail under the external oblique laterally, with its lower edge over the lower tail. Insert your fingers under external oblique superiorly and laterally to ensure that the mesh lies quite flat in the peripheral part of the pocket, though there may be a slight bulge centrally.


4. The mesh does need to be secured in place across the posterior wall of the inguinal canal. Although most use polypropylene sutures, it is possible to use staples or glue. Start the fixation by passing a 2/0 polypropylene stitch through the mesh and the tissues overlying the pubic tubercle and tying this. Use this to form a continuous locking suture between the lower edge of the mesh and the inguinal ligament, working from medial to lateral, extending to at least 2 cm lateral to the internal ring. Take irregular bites of the inguinal ligament to avoid splitting it and do not allow the lower leaf of the external oblique to roll in and be included in the sutures; if this happens, there will be no external oblique left to close. For the medial part of this suture line it is best to retract the cord downwards. Then, as the suture approaches the internal ring, move the cord cephalad and pass the needle under it to continue laterally. When suturing immediately in front of the femoral vessels be careful to take only the ligament and not a bite of a major vessel!


5. If the slit in the mesh is too short extend it so that the cord passes directly from the internal ring to the opening in the mesh. A bulky cord may be accommodated by making a small cut in the mesh at right-angles to the slit. If you made too long a cut, all is not lost; simply shorten the slit with one or two sutures.


6. Overlap the tails of the mesh by bringing the lower edge of the upper portion in front of the lower tail and securing it to the inguinal ligament with two interrupted sutures (or by including it in the lateral part of the continuous suture). The resulting opening in the mesh should be a snug, but not a tight, fit around the cord (Fig. 6.2B).


7. Now secure the medial and upper margins of the mesh with about six interrupted sutures, avoiding the nerves (Fig. 6.2B). These are most conveniently placed 0.5 cm away from the edge, so that the mesh lies flat on the underlying aponeurosis or muscle. The medial sutures are particularly important as there is less overlapping of the mesh there, making it a potential site for recurrence.


8. The mesh repair is now completed. It appears slightly redundant centrally but that does not matter.



9. Replace the cord in the inguinal canal.


10. Wash the inguinal canal with any remaining local anaesthetic, making sure not to remove it too quickly.


11. Close the external oblique aponeurosis with a synthetic absorbable suture, starting laterally and ending medially to reform the external ring snugly but not tightly around the emerging cord. Once again, take care to take bites at unequal distances from the edges; otherwise you will pull from the cut edges a strip of aponeurosis.


12. Appose the subcutaneous fascia with fine absorbable stitches and close the skin wound (see above).




Complications of open inguinal hernia repair


In addition to the complications mentioned in the section on general issues, there are others specific to the groin:



1. Scrotal complications: Ischaemic orchitis is an uncommon complication presenting as pain and swelling in the first few days after hernia repair. In a proportion of cases it results in testicular atrophy. Damage to the vas should be recognized and repaired at the time of hernia repair. Hydrocele formation is more common after transection of the sac and resorbs spontaneously in most cases. Genital oedema, relatively common in the first 3 days, settles spontaneously, requiring reassurance only.


2. Haematoma: Bruising can be significant, often involving the scrotum, to the alarm of the patient, developing a couple of days after surgery. Even significant haematomas can be left to resolve, although this may take months and does increase the risk of orchitis, mesh infection and possibly recurrence and groin pain.


3. Wound infections: Reddening of the wounds is not uncommon, but frank purulent discharge is. If this persists, be concerned about a mesh infection and consider removing the mesh.


4. Nerve injury: Some degree of transient numbness below and medial to the incision is very common and may persist with little disability. Of much more significance is the incidence of chronic residual pain that occurs in at least 3% of conventional hernia repairs.


5. Urinary problems: Make sure you are aware of the possibility of bladder injury and recognize it at the time of surgery. Treat it by primary repair and insert an indwelling catheter until a cystogram demonstrates healing. Postoperative urinary retention becomes more common with age, after general anaesthesia and following bilateral hernia repair and usually resolves following a 24-hour period of catheterization.


6. Impotence: This is an occasional complaint for which there does not appear to be an organic basis.



OPEN RECURRENT INGUINAL HERNIA REPAIR






Repair






OPEN STRANGULATED INGUINAL HERNIA REPAIR



Appraise




1. Most operations listed as strangulated hernia are carried out for painful, irreducible or obstructed hernias.


2. An open approach to the strangulated inguinal hernia repair is easiest and most common,


3. Strangulation results from venous obstruction, a rise in capillary hydrostatic pressure, transudation of fluid, exudation of protein and cells, and eventual arterial obstruction. Alternatively, the pressure of a sharp constriction ring at the neck of the sac may cause local necrosis of the bowel wall.


4. Once diagnosed, try to reduce the hernia, making emergency surgery unnecessary and allowing for an early elective operation. The effect of reassuring the patient, who is laid supine in the head-down position, encourages spontaneous reduction. Try to gently reduce the hernia, making sure not to hurt the patient. There is a slight but real risk that you may reduce the hernia en masse: that is, the hernia remains within the peritoneal sac, the neck of which remains as a constriction, so the strangulation is not relieved. Some hernias reduce spontaneously when the patient is sedated prior to operation, or when anaesthesia is induced.





Assess




1. If the history was short, the sac will frequently be empty by the time you expose it. The relaxation produced by the anaesthetic often succeeds when other conservative methods have failed to reduce a hernia. There is then no merit in exploring the abdomen. Repair the hernia as though this were an elective operation.


2. If bowel is present in the sac, do not let it slip back into the abdomen but gently draw it down into view. The bowel is likely to have suffered the greatest damage where it was trapped at the neck of the sac.


3. Feel the margins of the neck of the sac with a fingertip.


4. In Richter’s hernia, a knuckle of the bowel wall is trapped. The bowel lumen is thus not obstructed but the knuckle may become gangrenous and perforate.


5. Maydl’s strangulation is very rare. Two loops lie in the sac but the blood supply to an intermediate loop within the abdomen may be prejudiced so that it is gangrenous.



KEY POINTS


Is the bowel viable?




image If there is a sheen to the bowel wall, if it is pink or becomes pink after release, if the arteries pulsate, if peristalsis is seen, replace the bowel with confidence.


image If the wall is black, green or purple, with no sheen, if there is no pulsation in the mesenteric vessels or it is malodorous, resect it.


image If the bowel is congested, bluish or plum-coloured and still has a sheen, but vascular pulsations cannot be felt, then its viability is doubtful. Remember, however, that blood extravasated subperitoneally cannot be reabsorbed immediately so the colour may not change. Cover the bowel with warm moist packs for 5 minutes and re-examine it. If it has improved in appearance and mesenteric arterial pulsations are palpable it is probably viable.


image The critical areas are the constriction rings at the point of entrapment. These are white when the bowel is first drawn down but may be greenish or black if they are obviously necrotic. Re-examine doubtful rings after an interval to see if the blood supply returns. If it does not, the bowel must be resected. Occasionally it is possible to invaginate and oversew a doubtful ring.


image Experienced surgeons probably resect bowel less frequently than those who are inexperienced. The mucosa is more vulnerable than the seromuscularis to the effects of ischaemia and, if the outer layers survive, the mucosa may slough to leave an annular ulcer. When this heals a constriction may develop – the intestinal stenosis of Garré. The patient presents after an interval of weeks or months with incipient small-bowel obstruction. Provided this is recognized, a simple elective resection can be carried out.



Action




1. If the neck of the hernia sac is constricted, first draw down healthy bowel, then place an index fingertip on each side of the contents, nails facing outwards. Gently dilate the neck of the sac (Fig. 6.3). Make sure the bowel does not slip back. Draw it out to ensure that there is no peritoneal constriction and to expose healthy bowel.



2. If the bowel is viable, return it to the abdomen.


3. If necessary, resect a gangrenous segment of bowel, performing an end-to-end anastomosis.



Repair


After opening the sac and dealing with the contents, repair the hernia as though this were an elective operation, but if possible avoid the use of mesh if there has been bowel content spillage.


Mar 28, 2017 | Posted by in GENERAL SURGERY | Comments Off on Abdominal wall and hernias

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