CHAPTER 14 Pediatric surgery 572 Fluid and electrolyte management Normal fluid requirements The aim of appropriate fluid man agement is to maintain or achieve nor- mal hydration in a child. The best indicator of norm al hydration is an adequate urine output (neonates 2ml/kg/hr, children 1ml/kg/hr). All regi - mens depend on knowing the weight of the child, which ideally should be measured or can b e derived from the following calculation (in children between 1 and 10 years): Weight (kg) = (age + 4) (cid:215) 2 The following table gives a guide to normal fluid requirements in chil- dren. This takes in to account expected insensible losses, but increased losses (measured or occult) need to be added. Weight Fluid requirement for 24 hours Sodium mmol/kg/day Potassium mmol/kg/day <10kg 100ml/kg 3 2 10 \200\22320kg 1000ml + 50ml/kg +2 +1 >20kg 1500ml + 20ml/kg +1 +0.5 For example a 22kg child needs: 100ml/kg/day for the first 10kg = 1000ml 50ml/kg/day for th e next 10kg = 500ml 20ml/kg/day for the next 2kg = 40ml Total = 1540ml in 24 hours Electrol yte requirements Maintenance sodium and potassium requirements are in the above table. A ty pical intravenous fluid to achieve this would be 0.225% NaCl with 5% dextrose with 10mmol o f potassium added to each 500ml bag. Assessment of dehydration Levels of dehydration are co nveniently separated into mild (loss of 5% body weight in fluid), moderate (5 \200\22310%), and severe (>10%). In mild dehydration children may exhibit increased thirst with dry muco us mem- branes and a decreased urine output. As more fluid is lost, the child will become i ncreasingly oliguric leading to an altered conscious level, tachy- cardia, tachypnoea, and signs of reduced perfusion (increased capillary refill time). FLUID AND ELECTROLYTE MANAGEMENT1 573 Correction of dehydration Estimated fluid deficit (% loss of body weight (cid:215) weight ( cid:215) 10) needs to be added to normal daily maintenance and replaced over 24 hours. As, in most cases, there will have been loss of salt and water, the ideal fluid to replace the deficit is 0.9% NaCl. However, rather than administering two separate fluids, 0.45% NaCl wi th 5% dextrose is appropriate. Measure- ment of serum electrolytes is important to determin e how quickly to rehydrate (over 48 hours if sodium low or high), and whether to add potass ium to the solution. Administration of fluids If the gastrointestinal tract is functional this should be the pre ferred route of fluid administration. If a child will not drink, a feeding NG tube can be u sed. However, in cases where fasting is indicated, the intra venous route is used (see sect ion on Venous access). CHAPTER 14 Pediatric surgery 574 Vascular access Peripheral lines Commonly used sites for peripheral access include the dors um of the hand, antecubital fossa, long saphenous vein at the medial malleolus, dorsum of f oot, and the scalp in infants. Central venous access is re- quired for certain drugs and co ncentrated IV nutrition fluids. Peripherally sited central lines (epicutaneous lines) can p rovide more prolonged period of access. Current recommendations are to ensure the tip of th ese lines is not advanced into the right atrium. Intraosseous access Placement of a specifically designed needle into the intramedullary spa ce of the tibia can offer rapid access for resuscitation, fluids, and drugs. Demonstration of insertion should be in conjunction with formal resusci- tation training (APLS, PALS). Central access Common veins used for central access include internal and external jugular, subclavian and femoral veins. All can be accessed percutaneously, but the following is a de scription of the technique for open jugular vein access. Preoperative Ensure no bleeding tendency. Determine if any previous central lines \200\224 consider Doppler studies or venography if numerous previous lines. Consent should include r isk of bleeding, infection and inadvertent dis- lodgement. Position Supine. Head down with neck extension and facing to contralateral side. Incision Transverse neck incision about 2cm above clavicle. Procedure (cid:142)(cid:3) If external jugular vein obvious then blunt dissection to expose it. Control of vein achieved by passage of two 3/0 Vicryl ties around it. After tunneling the l ine, carry out a venotomy and insert the line. Advancement of line augmented by lateral tra ction of the vein by cranially sited tie. (cid:142)(cid:3) Gain internal jugular vein access by blunt dissection through two heads of sternocleidomastoid. Open the sheath overlying the vein. Clear the vein medially and later ally then grasp it with non-toothed forceps. Pass a right-angled dissector around the deep aspect of vein and then a sili- cone loop. Avoid rotation of vein by holding with forceps w hen loop is passed round. Repeat this action achieving cranial and caudal control. VASCULAR ACCESS1 575 (cid:142)(cid:3) Make a stab incision in the anterior chest wall. Tunnel the line in the su bcutaneous tissue to emerge at the neck incision \200\224aim to place the cuff >1cm from ex it site. Cut the line to appropriate length (above inter-nipple line). Flush line with hepa rinised saline. Deliver the vein into wound with silicone loops \200\224aim to tent vein op en with a small amount of intraluminal blood. Grasp superficial aspect of the vein with non -toothed forceps and carry out venotomy with scalpel or scissors. Advance line through veno tomy and determine the position of tip with X-ray (RA/SVC junction). Ensure line aspirates and flushes easily. If required, close the venotomy with a purse-string or interrupted 6/0 non-absorbable suture. (cid:142)(cid:3) Closure the skin with subcuticular 4/0 or 5/0 absorbable sutures and secure the line. Complications (cid:142)(cid:3) Hemorrhage (cid:142)(cid:3) Infection (5 \200\22310%) (cid:1 42)(cid:3) Dislodgement (cid:142)(cid:3) Pneumothorax in percutaneous subclavian insertion. CHAPTER 14 Pediatric surgery 576 Oesophageal atresia Incidence and presentation Incidence 1 in 3000 live births. Infants oft en coughing and \200\230mucousy \200\231 at birth. May have a color change with first feed . Unsuccessful passage of NG tube into blind ending upper oesophageal pouch (at about 12cm) , radiography confirms arrest in mid-thorax (T2 \200\2233). The history may reveal maternal polyhydramnios. Anatomy 85% have a lower pouch fistula to trachea at carina (TOF) (Fig. 14.1A). 10% will be pure oesophageal atresia (OA) \200\224no air in stomach on X-ray. Preoperative Carry out continuous suction of upper pouch by Replogle tube to avoid aspirati on. Investigate the child for associated VACTERL abnormalities. Renal ultrasound and echoca rdiography are important. If right sided aortic arch it may need to consider left thoracoto my. Position Right side up with right arm abducted over head. Incision Right posterolateral thoracotomy under angle of scapula. Procedure (cid:142)(cid:3) Open 4th intercostal space. Push parietal pleura away by inserti ng a damp swab through space. Insert self-retainer to spread ribs. (cid:142)(cid:3) Continue dissection posteriorly with damp pledgets, pushing the pleura ant eriorly (extrapleural approach). Identify the azygos vein and ligate it in continuity \200 \224then divide. Continue pledget dissection medially until the fistula is identified \200 \224it may be seen to inflate with ventilation. Clear the fistula with right-angled dissect or and control it with a silicone loop. (cid:142)(cid:3) Follow the fistula cranially until its attachment to trachea is identified. Excise the fistula at tracheal junction and close the trachea with inter- rupted 5/0 absorbable sutures. Check for air-tight closure under w ater. (cid:142)(cid:3) Identify upper pouch \200\224this is helped by advancement of Replog le tube. Carry out limited mobilization of upper pouch \200\224but exclude an upper pouch f istula (3%). Open the upper pouch transversely ensuring mucosa is opened \200\224the tube w ill advance into the field. (cid:142)(cid:3) Place four or five \200\230posterior wall \200\231 sutures with 5/0 absor bable material. Pass a 6F NG tube across the anastomosis into the stomach. Complete an inte rrupted single layer anterior anastomosis. (Fig. 14.1B). (cid:142)(cid:3) Allow the lung to reinflate and close the intercostal space. Insert an extrapleural chest drain. Close the muscle layers with 4/0 absorbable sutures. Subcuticular 5/0 absorbable sutures to skin. OESOPHAGEAL ATRESIA1 577 Postoperative Commence nasogastric feeds early. Carry out a contrast study at one week and encourage oral feeds if the anastomosis is satisfactory. Complications (cid:142)(cid:3) Anastomostic leak ( 8%) \200\224most can be managed conserva tively (cid:142)(cid:3) Anastomotic stricture (30 \200\22350%) \200\224Balloon dilatation o r bouginage (cid:142)(cid:3) Tracheomalacia \200\224if severe may require intervention (aor topexy or tracheostomy) (cid:142)(cid:3) Gastro-oesophageal reflux (30%) \200\224may require fundoplication. The mo rtality rate is low if the body weight is >2.5kg and no major car- diac defect. Management of pure OA Preoperative work-up as above. Management (cid:142)(cid:3) Managed initially by gastrostomy. (cid:142)(cid:3) Give good vo lume four-hourly feeds to encourage reflux up the distal pouch. (cid:142)(cid:3) Radiological assistance required to determine gap between proximal and distal pouches. (cid:142)(cid:3) Carry out definitive surgery as above. Proximal pouch Trachea Fistula at carina End-to-end anastomosis Distal pouch (A) (B) Fig. 14.1 Oesophageal atresia CHAPTER 14 Pediatric surgery 578 Intestinal atresia Duodenal atresia Associated with Down \200\231s syndrome (less than one third of cases). It pre- sents with bile vomiting and distended stomach, may have been iden tified on antenatal scans (polyhydramnios). There is a double-bubble on plain radiograph. T he second part of the duodenum is distended and atretic. 15% are above level of bile duct \200\224no bile is seen on aspirating the NG tube. Procedure (cid:142)(cid:3) Carry out an upper abdominal transverse laparotomy. (cid:142)(ci d:3) Identify the large baggy proximal duodenum and the small distal duo- denum. Mobilize the ends with care to avoid bile duct. (cid:142)(cid:3) Make a transverse incision to open the proximal duodenum and open the dist al duodenum longitudinally. Carry out a diamond end-to-end anastomosis with interrupted 5/0 absorbable sutures. (cid:142)(cid:3) Pass a transanastomotic feeding tube (transgastric or nasal). If the dista l duodenum cannot be mobilized and anastomosis cannot be performed safely, use the first lo op of jejunum to proximal duodenum. Jejunoileal atresia In this there is abdominal distension with a visible/palpable mass and vomiting (bile). The radiograph shows small bowel obstruction and ultra- sound reveals a cy stic dilated loop. Dilated pre-atretic bowel can be compromised by segmental volvulus. (cid :142)(cid:3) Type I (cid:142)(cid:3) Type II Obvious gap between ends but no defect in mese ntery (cid:142)(cid:3) Type III Gap in mesentery (cid:142)(cid:3) Type IV \200\230Apple pe el \200\231 distal intestine or multiple atresias (depending Intraluminal membrane (serosal surface looks intact) on classification) Procedure (cid:142)(cid:3) Make a transverse mid-abdominal incision. (cid:142)(cid:3) Untwi st any bowel volvulus. Carry out careful inspection of and irrigation through all bowel distal to atresia to establish patency of the lumen (contrast enema may have shown patent colon). (cid:142)(cid:3) Resect or taper any excessively dilate d proximal segment. (cid:142)(cid:3) Carry out a primary anastomosis if possible with singl e-layer of inter- rupted, 4/0 or 5/0 absorbable sutures (end-to-end or end-to-back). High s tomas lead to fluid and electrolyte disturbances and skin prob- lems \200\224avoid them if possible. Colonic atresia This presents with bile vomiting and abdominal distension. Contrast enema w ill demonstrate a microcolon to level of atresia. This may be therapeutic in meconium plug syndrome where there is an intraluminal cause for the obstruction. There is an association with Hirschsprung \200\231s disease. INTESTINAL ATRESIA1 579 Stomach Duodenum Pancreas Transverse incision DJ Flexure Longitudinal incision Duodeno-duodenal anastomosis Fig. 14.2 Duodenal atresia with corrective anostomosis Type I Type II Type III Type IV Fig. 14.3 Jejunoileal atresia CHAPTER 14 Pediatric surgery 580 Procedure (cid:142)(cid:3) Make a transverse mid-abdominal incision. Determine site of atre sia and the condition of proximal intestine. Resect any extremely dilated areas or any area s involved in perforation. (cid:142)(cid:3) Treat proximal atresias by a primary single layer anastomosis with interrupted 5/0 absorbable sutures (unless more than 3:1 discrepancy in the size). Treat di stal atresias (beyond splenic flexure) by forming a double barrelled colostomy and delay th e anastomosis until 3 \200\2236 months later. Anorectal atresia This presents with recognition of a blind perineum on routine examina- ti on or with absent stool passage and distension. It is usually anorectal and often associate d with a fistula to urethra (male) or vulvovagina (fe- male), urinary tract anomalies and s acral deficiency. A radiograph (pronogram) at 24 hours shows a dilated terminal rectum and gasless (atretic) zone between the rectum and perineum \200\224absent sacral verte- bral se gments suggest a poorer prognosis. Ultrasound (before gas reaches distal bowel) shows a dil ated terminal bulb of atretic bowel. Immediate management options (cid:142)(cid:3) Perineal operation to create neo-anus only ap propriate for very \200\230low \200\231 atresias. (cid:142)(cid:3) Sigmoid or right transverse defunctioning colostomy with later recon- stru ction by abdomino-perineal pull-through or posterior sagittal anorectoplasty (PSARP). Definitive procedure (PSARP) Catheterise bladder. Position Prone with support beneath hips to raise the sacral area \200\224legs abducted to give access to perineum. Procedure (cid:142)(cid:3) Carry out careful assessment of external sphincter fibers with m uscle stimulator and marking of skin anal site. (cid:142)(cid:3) Make a sagittal incision from coccyx to proposed anterior anal verge. Deep en the incision keeping strictly to the midline separating external sphincter fibers. The i nternal sphincter and levator muscle fibers should be seen and divided in midline. (cid:142)(cid:3) Enter the retrorectal space and identity posterior wall of terminal bulb o f the rectum, mobilize it in the extra-serosal plane. Separation from posterior urethra and prostate difficult as anatomical plane fused. (cid:142)(cid:3) Identify any urethral fistu la \200\224this may be aided by opening the rectum in midline posteriorly to approach fistu la directly from lumen. Divide the fistula flush with urethra and closed to avoid a diverti culum. (cid:142)(cid:3) Mobilize the rectum proximally/presacrally by further separation from urethra/prostate to allow advance to perineum without tension. Amputate the rectal bulb tip and anastomose with 5/0 absorbable sutures to putative anal skin site, which can be invert ed. Taper the rectal lumen tapered by posterior strip resection if markedly distended. INTESTINAL ATRESIA1 581 (cid:142)(cid:3) Carry out meticulous apposition of internal sphincter and levator fibers i n midline posterior to rectum with 3/0 absorbable sutures. Appose the subcutaneous fat tiss ue with 3/0 absorbable sutures. (cid:142)(cid:3) Close the wound with 3/0 absorbable sutures with interrupted to skin. Comp lications (cid:142)(cid:3) Anal recession and stenosis \200\224due to tension and ischaemia \200\224may need dilatation (cid:142)(cid:3) Skin excoriation \200\224unaccustomed to frequent loose stools (cid:142)(c id:3) Constipation \200\224inadequate defaecation reflex and evacuation (cid:142)(cid:3) In continence and soiling \200\224deficient muscle and muscle control. CHAPTER 14 Pediatric surgery 582 Gastroschisis Incidence, anatomy, and presentation This is a congenital abdominal wall defe ct to the right of the umbilicus with extruded, unprotected small and large bowel. Increasi ng incidence about 1 in 3000 live births. Associated with young maternal age. May be discov ered on antenatal scanning. Parents should be counseled about likely clinical course. A vag inal delivery not contraindicated. Preoperative At birth, herniated bowel should be wrapped in impervious cover to prevent eva porative losses. Venous access should be obtained and fluid resuscitation commenced. The in fant should be nursed in a position where mesentery is not on traction. Pass an NG tube. Position Supine. Procedure (cid:142)(cid:3) Cleanse herniated bowel with aqueous antiseptic solution. Determ ine size of defect. Pass finger through defect and gently stretch abdominal cavity. Attempt reduction of thickened, \200\230matted \200\231 bowel, which may be aided by small extens ion of defect laterally. If the bowel reduced under minimal tension close abdominal wall. (cid:142)(cid:3) Undermine skin edges with diathermy dissection to reveal abdominal wall mu scle which may be deficient. Clear the muscle layer to allow closure. (cid:142)(cid:3) If the defect is small it can be closed with pursestring 2/0 absorbable. C lose larger defects linearly with interrupted 2/0 absorbable sutures. Use 4/0 or 5/0 absorb able sutures to close the skin. Some surgeons advocate reducing the bowel without general a nesthetic. If there is doubt about intra-abdominal tension during reduction, a staged approach is advi sable. (cid:142)(cid:3) Attach Silastic sheeting around defect and tubularise it to create a \200\230silo \200\231 \200\224a ventral hernia within a prosthesis. Then suspend the \200 \230silo \200\231 ver- tically and the oedematous bowel gradually reduces over the next 5 \200\2237 days. (cid:142)(cid:3) Once the bowel is reduced, close the defect in the above manner. Newer devices allow application of the silo without suturing \200\224a self- expanding ring holds the sac within the defect. This can be applied in a sterile fashion without the need for general anesthetic. Consider placement of central (or epicutaneous) IV line at the time of surgery for parenter al nutrition. GASTROSCHISIS1 583 Postoperative NG tube on free drainage until reduction in bilious aspirates. The gut functi on is slow so feeds increased gradually \200\224average time to full feeds 21 \200\22328 da ys. Complications (cid:142)(cid:3) Outlook generally good. (cid:142)(cid:3) Extra-intestinal co ngenital anomalies rare \200\224associated atresia occurs in 10%. (cid:142)(cid:3) About 50% can be treated with primary closure. (cid:142)(cid:3) Short gut syndrome \200\224 \200\230functional \200\231 or due to loss of bowel. (cid:142)(cid:3) Rec ognized incidence of necrotising enterocolitis. CHAPTER 14 Pediatric surgery 584 Exomphalos (omphalocele) Incidence, anatomy and presentation Incidence decreasing. May pres ent antenatally \200\224amniocentesis advisable to determine karyotype. There are associati ons with chromosomal and cardiac anomalies. Cesarean section recommended to avoid rupture o f sac. Anatomy and management Represents failure of regression of extracoelomic midgut and physiol ogi- cal umbilical \200\230hernia \200\231 results in a membrane covered mid-abdominal her - niation of small bowel, large bowel, and liver. If minor (<5cm defect), surgical closure is possible but underdeveloped peritoneal cavity prevents reduction for most >5cm hernias. Conservative approach allows sac to thicken and cicatrise and results eventually in skin co vering, but requires later repair of residual ventral hernia. This page intentionally left blank CHAPTER 14 Pediatric surgery 586 Meconium ileus Presentation Abdominal distension, visible/palpable mass and vomiting (bile) . A radio- graph shows small bowel obstruction and ground glass appearance of meconium/gas mixture. The obstruction is caused by viscid, meconium pellets inspissated in distal ileum. The proximal ileum/jejunum obstructed and dilated: colon empty and unused (microcolon). It can be complicated by perforation (antenatal and postnatal), segmental volvulus and atresi a. Associated with cystic fibrosis (about 80%). Analyze karyotype and, if doubt remains, pe rform a sweat test later. Investigation Following plain radiography, perform water-soluble contrast enema for diagnos tic and possible therapeutic reasons. The microcolon will be outlined, and if contrast ente rs dilated loops of bowel the diagnosis is not in doubt. The lubricating effects of the con trast material may promote passage of normal meconium and a laparotomy may be avoided in ar ound 50% of cases. Incision Mid-abdominal transverse. Procedure (cid:142)(cid:3) Deliver all intestine into the wound. Peritoneal calcification i ndicates antenatal perforation. (cid:142)(cid:3) Open the dilated intestine and aspirate/flush viscid meconium. Resect any severely dilated ileum or sites of perforation. (cid:142)(cid:3) Attempt to flush distal bowel. If flushing successful, and no severe discrepancy between ends, primary anastomosis can be carried out. However, formation of dou ble-barrelled enterostomy is usually advised either through wound or adjacent to it. (cid:142)(cid:3) Other options include Bishop-Koop enterostomy (distal segment as stoma wit h proximal bowel anastomosed end-to-side) and Santulli enterostomy (proximal segment as sto ma with distal bowel anastomosed end-to-side). Postoperatively management If cystic fibrosis confirmed, ensure involvement of the appropri ate team. Offer parents genetic counseling for future pregnancies. Once estab- lished on en teral feeds, start pancreatic enzyme replacement to aid diges- tion. Use prophylactic antib iotics. Morbidity and mortality The outlook for children with cystic fibrosis continues to improve with current life expectancy in the 40s. The previously held opinion that infants presentin g with meconium ileus represented the severe end of the spectrum is no longer appropriate. This page intentionally left blank CHAPTER 14 Pediatric surgery 588 Hirschsprung \200\231s disease There is absence of ganglion cells (aganglionosis) of distal bowel for variable distance proximally from anus \200\224commonly only involves rectum wit h transition to normal at rectosigmoid junction. About 20% extend into the sigmoid with occ asional total colonic and, very rarely, whole bowel involved. If presents with delayed meco nium passage and progres- sive distension, there is often explosive release of gas and meco nium on digital examination. Radiography shows dilated colon to level of \200\230transi- t ion zone \200\231, coning down to normal caliber distal bowel. Confirmation by contrast ene ma/rectal biopsy. The condition may be syndromic with life- threatening respiratory insuffi ciency. Immediate management options (cid:142)(cid:3) Defunctioning colostomy (right transv erse) and delayed definitive procedure (cid:142)(cid:3) Saline bowel washouts and decompression with early progression to pull through procedure. Definitive procedure Options are endorectal (preserving rectal muscle coat \200\224Soave), rectum- removing (Swenson) or retrorectal (retaining distal rectal pouch \200\224 Duhamel). The Soave procedure is described (Fig. 14.4). Preoperative Carry out a bowel washout to ensure complete evacuation. Give intra- venous an tibiotics. Insert a urethral bladder catheter. Position Supine on small frame to hold baby in lithotomy position and permit access to abdo men and perineum. Approach Procedure commonly done transanally assisted by laparoscopic biopsies and bowel mo bilization. Carry out biopsy confirmation of transition zone and level of normal ganglion c ells. If laparotomy needed, perform a Pfan- nenstiel lower abdominal transverse incision wi th either retraction or cutting of rectus muscles. Procedure (cid:142)(cid:3) Insert perianal retracting sutures tied over colostomy bag ring to evert and expose lower anal canal. Infiltrate the anal mucosa with adrenaline (1:100 000 ) solution to minimize bleeding \200\224incised circumferentially just above dentate line. HIRSCHSPRUNG \200\231S DISEASE1 589 (cid:142)(cid:3) Develop dissection in the submucosal plane gradually everting mucosal tube . Carry out laparoscopic vessel cautery and mobilize the sigmoid colon as required. Identif y the point of full thickness bowel wall eversion, at the pelvic peritoneal reflection and carry out dissection through the muscle and serosal planes into the peritoneal cavity. Draw the bowel transanally until normal biopsy site identified. Amputate the colon at this poin t and anastomose to anal mucosal cuff with multiple 5/0 absorbable sutures working in quadr ants \200\224avoid tension. (cid:142)(cid:3) If laparotomy performed, close the wound with 3/0 continuous absorbable to muscle and fascia and 4/0 subcuticular sutures to skin. Complications (cid:142)(cid:3) Pelvic infection/peritonitis from perforation/contamination (cid:142)(cid:3) Anal stenosis/stricture from ischaemia or tension (cid:142)(cid:3) Constip ation \200\224suggests residual aganglionosis (cid:142)(cid:3) Urinary dysfunction \200\224 pelvic splanchnic nerve damage (cid:142)(cid:3) Enterocolitis \200\224a risk for all Hirsch sprung \200\231s cases and not removed by successful surgery. Urethral catheter Colostomy ring Anal canal Everting sutures Fig. 14.4 Soave approach for Hirschsprung \200\231s disease CHAPTER 14 Pediatric surgery 590 Necrotising enterocolitis This is a transmural inflammatory process occurring throughout th e GI tract \200\224probably related to ischaemia, invading bacteria and substrates in feed. Onset acute often in newborn complicated by prematurity, infec- tion, intestinal obstructi on or other cause of stress. It presents with systemic evidence of lethargy, pallor, distre ss with bile vomiting, abdomi- nal distension, bleeding per rectum and signs of abdominal w all redness, oedema and tenderness, mass, crepitus on palpation. Abdominal radio- graph may show intramural gas (ring and tramline signs) and free intrap- eritoneal gas signifying pe rforation. There is rapid progression to necrosis and perforation mandates surgery. Options (cid:142)(cid:3) For very sick, premature, low birth weight babies peritoneal drain age alone may be safest (cid:142)(cid:3) Laparotomy with resection, exclusion and stoma decompression is more definitive. Preoperative management Correction of acidosis, hypothermia, anemia, and coagulation disord ers and give adequate fluid and antibiotic resuscitation improve the chances of successful outcome. Position Supine. Incision Transverse muscle cutting supraumbilical. Procedure (cid:142)(cid:3) Aspirate faeculent and bile-stained fluid and culture for bacter ia. Care- fully separate and explore the inflamed, adherent and friable bowel loops. Evacua te intraloop and loculated abscesses and fluid collections. (cid:142)(cid:3) Make assessment of bowel viability and need for resection. Carry out multi ple resections and stomas or \200\230clip and drop \200\231 (isolating viable, closed segm ents in peritoneal cavity to await later restoration of con- tinuity). Stoma formation is i nvariably needed as primary anastomosis in this situation is highly risky \200\224 secondar y restoration of continuity is safer. If there is very extensive ischaemic damage this may preclude resection because of \200\230short bowel \200\231 risks. Carry out closure and ta ke a second look at 48 hours \200\224close the abdomen using a prosthetic patch both reliev es tension (promoting reperfusion) and facilitates second laparotomy. Bring out stomas thro ugh wound or through a separate incision. NECROTISING ENTEROCOLITIS1 591 (cid:142)(cid:3) Persisting inflammation and wound infection is a high risk \200\224close wound with 2/0 or 3/0 continuous absorbable sutures to peritoneum, muscle and fascia with s ubcuticular 4/0 continuous absorbable or monofilament sutures to skin. Complications (cid:142)(cid:3) Persisting systemic problems of acidosis, sepsis, coagulatio n disorder (cid:142)(cid:3) Intraperitoneal sepsis/abscess formation (cid:142)(cid:3) React ionary/secondary intraperitoneal bleeding (cid:142)(cid:3) Inadequate absorption and diarrh ea due to mucosal change (cid:142)(cid:3) Short gut syndrome following resection and need f or parenteral nutrition (cid:142)(cid:3) Later stricture and obstruction due to partial ischaemia (cid:142)(cid:3) High mortality related to multi-system failure. CHAPTER 14 Pediatric surgery 592 Sacrococcygeal teratoma This tumor develops in utero and involves all three germ layers. It is occasionally malignant. It may be detected antenatally by raised maternal alphafetoprot ein levels and abnormal ultrasound scan \200\224occasionally there are severe complications of fetal hydrops, which require premature delivery. It often presents as a large mass in p erineum/pelvis between rectum and sacrum/coccyx causing gross pelvic distortion and limb di s- placement. It is cystic or solid with variable vascularity (can present with high output cardiac failure and excessive bleeding). Doppler ultrasound and MRI imaging are useful to define blood supply and direct exploration to the abdomen or perineum. Preoperative (cid:14 2)(cid:3) It is essential to have good intravenous access and blood cross- matched in case of excessive bleeding from pelvic vessels, insert a urinary bladder cathete r. (cid:142)(cid:3) The approach to the tumor is perineal/pelvic but occasional an initial laparotomy is required to control major blood vessels. Position Prone with sacro-perineal area elevated with support beneath the pelvis. An iodine soaked gauze packed into rectum will help to define anatomy. Incision Make a chevron shape d incision with V based over lower sacrum and limbs of chevron extending either side of tum or. Procedure (cid:142)(cid:3) Elevate skin flaps to expose the tumor and dissect it from p osterior rectum anteriorly. (cid:142)(cid:3) Amputate coccyx to allow dissection of tumor in anterior sacral space. Use electrocautery sparingly to avoid pelvic autonomic nerve damage. The tumor often has pseudocapsule which aids its definition and separation from pelvic floor and viscera. (cid:142)(cid:3) If there is extensive intrapelvic extension, it may be necessary to turn the patient supine and explore the tumor from an abdominal approach. Carry out careful liga tion of blood supply from hypogastric, presacral and internal iliac vessels before removal. Haemostasis secured by ligature and cautious electrocautery. (cid:142)(cid:3) Approximate the pelvic muscle layers with 3/0 absorbable sutures. Close the chevron incision as an inverted Y with 4/0 absorbable and a suction drain if larg e residual presacral space. Remove the gauze packing from rectum. SACROCOCCYGEAL TERATOMA1 593 Complications (cid:142)(cid:3) Wound infection \200\224related to major tissue disturbance at tumor removal (cid:142)(cid:3) Wound haematoma \200\224large potential dead space (cid:142)(cid:3) Diffic ulty with bowel control related to major pelvic muscular dysplasia (cid:142)(cid:3) Problem s of incontinence related to pelvic nerve distortion/damage (cid:142)(cid:3) Lower limb dys function related to initial major hip/pelvic distortion. Sacrococcygeal teratoma Chevron incision Fig. 14.5 Excision of saciococcygeal teratoma CHAPTER 14 Pediatric surgery 594 Congenital diaphragmatic hernia (CDH) Incidence and presentation About 1 in 3000 live birth s (includes in utero losses). Antenatal diagnosis is made in 50% if detailed scans routinel y available (<20% otherwise). Postnatal presentation is with immediate respiratory compromi se of newborn, which deteriorates with bag and mask ventilation (inflation of intrathoracic stomach). Intubate and ventilate the baby and pass a large (10F) NG tube. Confirm diagnosi s by radiography. Small percentage diagnosed late (minor symptoms). Anatomy The Bochdalek defect is most common (posterolateral). The Morgagni defect (anteriom edial) is most often a late presentation. Hernia of intra- abdominal viscera into chest \200\224commonly small and large intestine, also stomach, liver, spleen and occasionally ki dney also occurs, 80 \200\22390% left sided. Pulmonary hypertension is secondary to pulmona ry hypoplasia. Echocardiography aids diagnosis and can monitor treatment. Timing of surgery and adjuncts Delayed surgery now standard practice. It is not advisable t o proceed to repair until ventilatory parameters have improved. Newer treatments include in haled nitric oxide, surfactant, extracorporeal membrane oxy- genation and sildenafil. Gentl e ventilation with permissive hypercarbia is recommended. This includes high frequency osci llation. Position Supine. Incision Ipsilateral transverse upper quadrant or subcostal (1cm below margin). Procedure (cid:142)(cid:3) Open peritoneum and retract upper edge of wound to reveal anteri or rim of diaphragm. (cid:142)(cid:3) Gently deliver herniated contents from chest into wound. Carry out soft re traction of liver and gut to expose size of defect. Look into hemithorax to determine if sa c present. If sac is present, excise it. Iden- tify the posterior rim and mobilize it. (cid:142)(cid:3) Insert interrupted horizontal mattress sutures with 2/0 or 3/0 non- absorbable. Place each suture individually and tie after all in place. If no posterior rim and defect large, a patch (PTFE, Silicone) may be used. Cut patch to appropriate size and s uture in place with 2/0 or 3/0 non- absorbable sutures. Sutures may be inserted around ribs posteriorly. Chest drains are used uncommonly. (cid:142)(cid:3) Close the wound in layers with 3/0 absorbable and subcuticular 4/0 or 5/0 absorbable to skin. CONGENITAL DIAPHRAGMATIC HERNIA (CDH)1 595 Mortality Mortality of live born infants around 40%, is usually due to intractable pulmonar y hypertension. Some centers report improved survival with multidisciplinary directed appro ach. Complications (cid:142)(cid:3) Recurrence of hernia (cid:142)(cid:3) Chronic lung disease ( cid:142)(cid:3) Intestinal obstruction \200\224due to adhesions or volvulus (universal mesentery) (cid:142)(cid:3) Gastro-oesophageal reflux. Diaphragmatic eventeration The diaphragm is present but muscle atrophied. Presentation is s imilar to CDH although it is often less severe. Radiograph shows pronounced smooth dome of elevated diaphragm and ultrasound scanning shows paradoxical movement of diaphragm (upwards on inspiration). Treatment is by plication of diaphragm through abdominal incision or thor acotomy. Left lung Right lung Bowel loops Heart Diaphragm defect Liver Fig. 14.6 Diaphragmatic hernia CHAPTER 14 Pediatric surgery 596 Spina bifida There is defective neural tube formation with exposed neural tissue at the are a of failed posterior vertebral arch development often in the lumbosacral spine. It is ofte n prenatally detected by raised maternal alphafetoprotein levels and anomalous ultrasound s can. Associated con- ditions are hydrocephalus (cognitive dysfunction), neurogenic bladder and bowel (incontinence) and lower limb paresis/paralysis and sensory losses. The back lesi on may be \200\230closed \200\231 (meningocele) or \200\230open \200\231, leaking CSF (my elomeningocele). Open lesions expose the newborn to risks of further neurological damage an d ascending CNS infection and warrant early operation to mobilize and close the meningeal m embranes, fascia and skin over the exposed central nerve cord. Preoperative Antibiotic prophylaxis. Position Prone with support to upper chest and pelvis to avoid ventilatory prob- lems relat ed to abdominal pressure. Procedure (cid:142)(cid:3) Outline the exposed neural plaque and meninges by a skin incisio n. (cid:142)(cid:3) Tabularise the nerve cord, if possible, with very fine (5/0, 6/0) absor b- able continuous sutures to minimize CSF leak. Close the dura similarly with 5/0 or 6/0 a bsorbable. Close the fascial layer in a vertical line achieved by longitudinal incision in the erector spinae fascia which is reflected medially to the midline over the bifid spines. (cid:142)(cid:3) Close the skin with 3/0 absorbable in either vertical or transverse line w ith wide undermining to release tension \200\224occasionally rotation or lateral release fl aps are needed for a wide defect. Insert a suction drain, useful if extensive undermining o f skin. Complications (cid:142)(cid:3) Wound infection (cid:142)(cid:3) Skin necrosis/dehiscence du e to excessive tension (cid:142)(cid:3) Ascending CNS infection and meningitis (cid:142)(ci d:3) More rapid progression of hydrocephalus related to cessation of CSF leak. This page intentionally left blank CHAPTER 14 Pediatric surgery 598 Release of tongue tie A tight frenulum of the tongue can restrict movement to extent of int er- ference with feeding or speech \200\224rarely the case if tip protrudes beyond lower te eth. Anxiety about possible effects is a common reason for referral. Reassurance alone is o ften sufficient. Procedure Usually under general anesthesia but local possible as procedure takes seconds. ( cid:142)(cid:3) Tongue tip grasped with forceps and drawn upwards and forwards to expose ti ght border of frenulum \200\224divided with scissors to release tongue. Two leaves of frenu lum divided further posteriorly for greater advance and the frenular artery in midline avoi ded. (cid:142)(cid:3) This procedure is usually bloodless but significant bleeding requires suture (4/0 absorbable) to artery at base of frenulum. Complications (cid:142)(cid:3) Reactionary bleeding \200\224may demand re-exploration and s uture of artery (cid:142)(cid:3) Inadequate release and residual restriction. This page intentionally left blank CHAPTER 14 Pediatric surgery 600 Ranula Anatomy and presentation This is a smooth, bluish, cystic swelling arising in floor of mouth beneath tongue from sublingual gland. It may cause problem with feeding, inter- fe rence with speech development and cosmetic concern but there are rarely symptoms of pain/di scomfort or infection. Preoperative Nasal endotracheal intubation improves the surgeon \200\231s access to oral ca vity. Jaw opened with dental gag and hypopharynx/posterior airway packed to avoid potential aspiration. Procedure (cid:142)(cid:3) Holding suture in tongue tip may help control and access. (cid:1 42)(cid:3) Excise small, discrete, well-defined cysts completely with repair of mucosa with interrupted absorbable 4/0. (cid:142)(cid:3) Make no attempt to excise larger cysts as risk of damage to lingual nerve and submandibular duct. (cid:142)(cid:3) Excise a segment of anterior cyst wall with scissor dissection or elec- tr ocautery to open and drain cyst. Outer (mucosal) and inner (duct epithelial) linings of cys t then sutured together (with continuous absorbable 4/0) to control bleeding, prevent re-ad herence and produce a stoma in cyst wall (marsupialisation). Cyst then rapidly shrinks down and sublingual saliva drains via stoma. Complications (cid:142)(cid:3) Infection if oral hygiene poor and foreign material lodges i n cyst (cid:142)(cid:3) Bleeding from resected cyst wall (cid:142)(cid:3) Recurrence if mar supialisation inadequate. RANULA1 601 Support suture Tongue Ranula Marsupialised wall Fig. 14.7 Marsupialisation of ranula CHAPTER 14 Pediatric surgery 602