19 Anaesthesia for paediatric maxillofacial surgery

Probably the most common procedures undertaken by maxillofacial surgeons in children are either explorative dental procedures or soft tissue repair following facial trauma. Another large group of work is related to the primary and secondary management of children with cleft lip and palate. Maxillofacial surgeons work as part of a multidisciplinary team and services are configured in many different ways according to local arrangements. For example, primary cleft work is done in some areas by maxillofacial surgeons and in others exclusively by plastic surgeons. Similarly, craniosynostosis may be managed by maxillofacial, craniofacial, or neurosurgeons depending on local practice and expertise.

Whilst the principles involved in managing an anaesthetic in the older child are similar to adult practice, the expertise of the paediatric anaesthetist and the perioperative care of the paediatric nursing and medical teams are required in managing babies and young children.

The main groups of children who will need maxillofacial input are illustrated in Table 19.1.

Review of previous anaesthetic charts will reveal any previous difficulties on induction of anaesthesia, management of the airway, and complications on recovery. History of respiratory compromise such as presence of a significant pectus excavatum (an indicator of chronic airways obstruction), tachypnoea, tracheal tug, use of accessory muscles of respiration, or cyanosis have important anaesthetic implications. History of failure to establish adequate nasal breathing (choanal atresia), episodes of arterial oxygen desaturation related to airway obstruction, history of snoring, airway obstruction intermittently (especially during sleep), obstructive sleep apnoea (OSA), central apnoeas, preoperative oxygen requirement (especially note any recent increase), dependence on preoperative ventilation or continuous positive airway pressure (CPAP), history of feeding difficulties, or failure to thrive should be elicited. In children with syndromic/dysmorphic features, the preoperative workup should include screening for the presence of coexisting congenital malformations, including cardiac defects.

A preoperative visit enables the establishment of rapport with the child/parents, helps to allay anxiety, and gives the opportunity to discuss the anaesthetic plan. Midazolam is the mainstay of paediatric premedication. Whilst sedative premedication is contraindicated in a child with a precarious airway it is often useful in anxious children who do not have airway compromise. Sedative premedication is usually avoided in infants with cleft palate.

Anticholinergics such as atropine or glycopyrrolate are particularly useful if an advanced airway technique is to be used. By decreasing the airway secretions a gaseous induction is smoother and laryngospasm less likely. The view via the fibreoptic scope is better and clearance of secretions is much less of an issue. This is particularly so when using the smallest fibreoptic scope which does not have a suction channel.

Children are allowed to have clear fluids until 2 hours, breastfeeding until 4 hours, and formula feeds until 6 hours, prior to surgery¹.

As an anaesthetist the main question is whether you expect to have difficulties in managing the airway or intubation in a syndromal child. Fortunately, it is very rare for the paediatric airway to be unexpectedly difficult to manage. Routine preoperative tests used in adult practice to identify the difficult airway (see Chapter 4), have not been validated in paediatric practice. However, there is usually plenty of warning that the anaesthetist may have difficulties with airway management and therefore preparation is possible.

Inhalational anaesthesia remains the preferred technique of induction for management of the difficult pediatric airway^{2  ,3}. Intravenous access is secured prior to intubation.

Most difficult intubations in paediatrics are predictable as they are in syndromal children. Airway management should be individualized based on careful history and physical examination of soft tissue and bony abnormalities in each child. There is an increasing range of specialized airway devices and equipment available for use in children. A selection of Straight, Macintosh, Miller, McCoy, and video laryngoscopes are available in a range of sizes^{4  ,5}. Paediatric fibrescopes are available down to 2.2 mm in external diameter. However, the smallest scope with a working channel is 2.8 mm (Karl Storz, Germany) in external diameter, which can be used with a 3-mm tracheal tube⁶.

Children will rarely tolerate awake fibreoptic intubation (FOI), so a technique that will work in the anaesthetized child is essential. There are two main issues to consider. Firstly, how to keep the child anaesthetized and monitored whilst doing the FOI and secondly, how to actually achieve the intubation. Laryngeal mask airway (LMA) in combination with a flexible fibrescope serves as an important tool in handling paediatric difficult airway and intubation. Use of a LMA allows anaesthesia to be maintained with a volatile agent, provides a conduit for tracheal intubation, and, most importantly, provides a secure airway during spontaneous ventilation until intubation is accomplished.

A wide selection of tracheal tubes has been designed for paediatric use. Surgical requirements tend to drive the choice of either an oral or a nasal tube. Uncuffed tubes are still the tube of choice for young children and are widely recognized as safe⁷. However, cuffed tracheal tubes, designed specifically for paediatrics, are available in all sizes and there is increasing interest in using these, though this remains controversial^{8  –10}.

Most surgery on the airway will require use of a throat pack. It is used to provide a seal around the uncuffed tracheal tube, absorb blood and debris, and help stabilize the tracheal tube in the required position. This seemingly simple piece of equipment is fraught with potential for harm (see Chapter 12). Vigilance is required when a throat pack is used and the insertion and removal of the pack is carefully documented.

Any intraoral/nasal surgery is associated with the risk of contamination with oral flora and broad-spectrum cover is required. Local practices dictate the choice of antibiotic prophylaxis used for surgery. Co-amoxiclav is a frequent choice if the child is not penicillin sensitive. When skin or bone grafting is planned, the infection risk is more likely to be due to Staphylococcus aureus and antibiotic prophylaxis is adjusted appropriately according to local guidelines. Antibiotic prophylaxis for children with cardiac lesions has been recently reviewed and the majority of conditions no longer require antibiotic prophylaxis^{11  ,12}.

For minor surgery perioperative fluids are not essential, however, there is good evidence that recovery is improved, and nausea and vomiting is less, if children are given fluids and are not required to drink until they are inclined to do so. Perioperative fluid management must be carefully managed, and it is divided into provision of a maintenance fluids and replacement fluids.

Maintenance fluids are given as isotonic crystalloid infusions. There has been much debate of the ‘ideal’ fluid to use in children as a maintenance solution. The suggested volumes are based on early work on the water needs of children undergoing surgery¹³.

Volume required for maintenance:

Balanced isotonic salt solutions such as Hartmann's are satisfactory for perioperative use in most children; however, practice varies regarding the particular choice of fluids nationally and internationally. Recent guidelines have been published to inform and guide this discussion¹⁴. It is important to warm the fluids and monitor temperature to keep the child warm between 36–37°C.

Postoperative fluids are usually restricted to 50–75% of the estimated hourly maintenance volume. Children should be able to drink early after maxillofacial surgery and intravenous fluids are reserved for those who are unable to drink and those who have an intraoral repair should oral feeding if contraindicated. If postoperative fluids are required it is important to remember that replacement of surgical losses requires colloid or blood products and maintenance fluid requirement requires an infusion of either Hartmann's or 0.45% saline in 5% dextrose. If the child is not able to feed, then the blood glucose, urea, and electrolyte should be checked at least 1 hour after surgery, then every 4 hours and any abnormalities actively corrected.

Major maxillofacial surgery may result in both prolonged surgery and extensive blood loss and these are replaced with a mixture of blood products and colloid guided by the type and volume of measured and ongoing losses.

Regular point of care estimations of haemoglobin concentration and electrolyte measurements are essential to guide the choice of fluid. Protocols have been published which give clear guidelines for postoperative fluid replacement with the goal of maintaining a haemoglobin above 7 g/dl, ensuring satisfactory haemodynamics and be responsive to ongoing losses if present¹⁵.

Children with craniofacial or mandibulofacial dysostosis are at high risk of postoperative respiratory compromise including obstructive sleep apnoea¹⁶. These patients may benefit from the insertion of a nasopharyngeal ‘prong’. The prong fashioned from a paediatric tracheal tube is inserted at the end of the surgery, to keep the airway patent¹⁷. However, the use of a nasal tracheal tube should be avoided in any child who has had a pharyngoplasty. Prolonged surgery and excessive pressure exerted on the base of the tongue by the retractor may result in postoperative oedema causing potential airway obstruction¹⁸. A careful assessment of the airway and planning is essential prior to extubation. If stridor is present, nebulized adrenaline and a single bolus of intravenous dexamethasone are given and this is very effective in decreasing the risk of laryngeal oedema. Nursing these patients in head-up position helps in reducing oedema. In some cases, it may be necessary to intubate and ventilate them for a period of time.

A child who has a precarious airway preoperatively will be better able to thrive, grow, and be safe in the early postoperative period, if they have a tracheostomy. Early tracheostomy may be required in about 17–50% of infants with craniofacial dysostosis (e.g. Apert, Treacher Collins syndromes), having severe airway obstruction^{19  ,20}. Successful decannulation of these children may take several years until midface advancement is complete¹⁹.

A tracheostomy is sometimes essential in order to undertake major facial surgery safely. It is useful to remember that a tracheostomy can be done while the airway is being maintained with a tracheal tube, a LMA, a nasopharyngeal airway, or indeed a face mask. During the management of major paediatric facial surgery, the tracheostomy is kept until the series of operations is completed.

There is morbidity and mortality associated with tracheostomy, which can be early or late. Early complications include local trauma, bleeding, pneumothorax, pneumomediastinum, subcutaneous emphysema, and tube accidents such as accidental displacement or blockage of the tracheal tube. Late complications include tracheal stenosis, granulation formation, subglottic stenosis, and long-term speech damage²¹.

Postoperative nausea and vomiting (PONV) is a common sequel. Some children, particularly those with known travel sickness are particularly prone to PONV and it is aggravated by blood being accidentally ingested postoperatively and by the use of opiates. PONV can be managed using the Association of Paediatric Anaesthetists (APA) guidelines which recommend a combination of ondansetron and dexamethazone prophylaxis²².

Multimodal analgesia is routinely used. Most children will be satisfactorily managed with a combination of effective local anaesthetic, usually provided by the surgeon and paracetamol 15 mg/kg intravenously 6 hourly or 15–20 mg/kg rectally 6 hourly. Non-steroidal anti-inflammatory drugs (NSAIDs) are used if appropriate. NSAIDs (ibuprofen and diclofenac) have not been associated with an increased risk of perioperative bleeding in children²³. However caution is exercised in surgical procedures with a high risk of bleeding.

Remifentanil is a predictable opioid that promotes rapid recovery and haemodynamic stability in paediatric anaesthesia. There are advantages for its use in neonates and infants due to their higher clearance of remifentanil²⁴. If morphine is used, then it is usually given 40 minutes prior to the end of the procedure for optimal analgesia without compromising recovery²⁵.

Postoperatively, simple oral analgesics given in a regular dose regimen are very effective. Guidelines are available for dose regimens and balanced analgesia²⁶.

Local anaesthetic given either as local infiltration or as specific nerve block is surprisingly effective. These include lidocaine 1% (maximum dose limited to 3 mg/kg), lidocaine 1% with adrenaline (1: 200 000 or 1: 80 000) up to a maximum dose limited to lidocaine 5 mg/kg and that of adrenaline limited to 5 mcg/kg or levobupivacaine 0.25% up to a maximum dose limited to 2.5 mg/kg (2 mg/kg in neonates).

Cleft lip and palate are the commonest craniofacial anomalies²⁷. Cleft lip occurs in 1 in 600 live births. Isolated cleft palate occurs in about 1 in 2000 live births. The clefts may be incomplete or complete involving lip, alveolus, hard and soft palate. The objective of correction of cleft lip/palate is to get a good cosmetic and functional outcome, which includes normal hearing and speech. A centralized care model, with eight to 15 regional centres and a multidisciplinary cleft team approach are recommended for improved outcome in these group of patients^{27  ,28}. A child with a cleft will often need a planned series of operations spread over many years, depending on the severity of the condition. They also need the support of the wider cleft team comprising of maxillofacial, plastics, ear, nose, and throat (ENT), orthodontic surgeons, paediatrician, speech therapists, specialist nurses, educational support, and psychologists. Surgery is divided into primary and secondary cleft surgery.

Repair of cleft lip is done at 2–3 months of age in healthy infants and usually delayed until 60 weeks postconceptual age in premature infants. Neonatal repair of cleft lip is undertaken in some centres. Early repair may improve mother–infant interactions and maintain normal cognitive development of infants²⁹. However, the potential for perioperative complications in the neonatal period must be carefully considered³⁰. If surgery is done in the newborn, there is the possibility that other congenital abnormalities will not yet have been detected and there is a risk that the neonate will revert to a transitional circulation perioperatively. In addition, closure of the lip and the anterior palate at the first operation, at about 3 months, results in better outcome in the long term.

Palate repair is considered at 9–12 months of age when the baby is starting to try to speak, this is timed to prevent delay in speech development. Infants with associated syndromes such as Pierre Robin, who have severe airway obstruction in the neonatal period are at high risk of postoperative hypoxaemia and will benefit from postponing the palate repair until the age of 12–18 months. Some units will delay surgery until a baby has reached 5 kg taking this as an indicator that the child is managing to thrive³⁰. The timing of cleft surgery is in part determined by the child's age (Table 19.2).

Whilst the majority of children with cleft lip and palate have no other abnormalities, this condition is associated with a wide variety of syndromal or dysmorphic features (Table 19.3). A more extensive cleft seems to be associated with a higher risk for associated malformations.

There is an increased prevalence of congenital heart disease in children with cleft palate³¹. Therefore it is important to perform a careful clinical examination, record preoperative oxygen saturation, and consider echocardiography.

Chronic rhinorrhoea is common in infants with cleft palate due to nasal regurgitation during feeds. If active infection is present, especially in children with a wide cleft, primary palate surgery is postponed to reduce perioperative respiratory complications³².

The presence of a cleft palate can make sucking difficult so that breast- or bottle-feeding can be difficult to establish. Most infants will thrive with careful spoon or bottle-feeding using modified teats. Occasionally nasogastric feeding is necessary, for instance in infants with severe Pierre Robin sequence.

Partial upper airway obstruction is present in some infants with micrognathia especially during sleep. If uncorrected, resultant hypoxia may lead to right ventricular hypertrophy and, rarely, cor pulmonale³³. Conservative measures like prone/lateral positioning are useful in mild cases and a range of surgical methods are used to relieve airway obstruction in severe cases³⁴.

Occasionally babies will be oxygen dependent, or may need long-term nasal CPAP, usually because of a combination of partial airway obstruction and chronic lung disease. These children are particularly at risk of severe airway obstruction once the palate is closed. It is important to identify those patients prior to surgery so that they can be monitored and managed appropriately⁴². A small minority may need a temporary tracheostomy to cover the perioperative period³⁴.

In the healthy baby for a cleft lip repair, only a haemoglobin test is required; however, when palatal surgery is planned a group and save is also done. It is unusual for a child to actually require blood transfusion for closure of cleft palate.

A palatal fistula may occur as a late complication of palatal closure. These require re-operation and the general principles of management are the same as with primary palate closure.

Children with a repaired cleft lip and palate may have difficulties with the development of their speech. This usually presents in the 6–8-year age group and is identified when the child's speech is compromised so it is identified at school. Mostly the issue will be around a hypernasal speech brought about by impaired palatal function, velopharyngeal insufficiency (VPI). Children will be assessed by the speech therapist who is an integral part of the cleft team. Pharyngoplasty or palate re-repair may be recommended as this will tense up the palate and improve phonation so clarifying the speech. About 25% of children with cleft palate may need this procedure⁵². Palate re-repair has a lower morbidity and is more physiological than a pharyngoplasty or pharyngeal flap surgery^{51  ,53}.

As the surgery is in the posterior pharynx a nasal tube is contraindicated. An oral RAE tube fixed in the midline is ideal. Use of a throat pack is essential. Local anaesthetic infiltrated into the palate is very effective. Simple analgesics are all that is required postoperatively. Following a pharyngoplasty the airway is not usually compromised and recovery is uneventful. Depending on the type of pharyngoplasty there may be little room for nasal escape of air post pharyngoplasty.

It is important to remember that any child who has had a pharyngoplasty has a reduced nasal airway and future use of a nasal tracheal tube should be avoided whenever possible so as to ensure the pharyngeal repair is not compromised. If a nasal tube is essential due to future surgical needs then a fibreoptic scope should be used to guide intubation.

Children with a cleft palate will have an incomplete dental arch. The size of the alveolar defect will depend on the initial extent of the cleft. As orthodontic techniques have improved, the procedure of grafting bone fragments to the alveolar cleft has become increasingly common. An alveolar bone graft (ABG) is done when the secondary teeth are established, at about 8–12 years of age.

A bone graft is taken either from the anterior iliac spine or from the tibia. The ABG provides a continuous maxillary arch, closes the oronasal fistula, and provides bony support for the teeth. If the cleft was bilateral it is usual to do an ABG to each side independently. The success rate for ABG is 81–90%^{54  ,55}. Complications include failure of the graft, insufficient bony structure post ABG, pain at the donor site, and infection. Donor site complications are infrequent when the anterior iliac spine is the source of the bone graft. In contrast, bone grafts retrieved by trephining of the tibia can give rise to a number of serious complications. Tibial fractures are reported in up to 2.7% of patients having this approach causing significant disruption to the child's life⁵⁶.

As the child grows, the discrepancy between the maxillary underdevelopment and the normal mandibular growth becomes more apparent. Surgically this requires a Le Fort I maxillary advancement and sometimes a mandibular osteotomy and reconfiguration. This is major surgery and is not undertaken until approximately 15 years of age when the bony development of the face has mostly been completed. The anaesthetic management of such cases is discussed in Chapter 18.

One important aspect is the postoperative care of children who have intermaxillary fixation (IMF). Any child in IMF without a tracheostomy should be nursed on an Intensive Care Unit (ICU) for the first postoperative night⁵⁸. Should airway compromise occur, the IMF wires need to be cut to allow intubation. The position of each wire should be clearly documented and it is essential wire cutters are kept at the bedside at all times.

IMF is less commonly used now as interocclusive elastic bands placed between upper and lower jaws are satisfactory and can be fitted the day following surgery when the child has recovered from anaesthesia. This means that children can be managed on the routine maxillofacial ward rather than in an ICU.

Depending on the airway assessment a fibreoptic technique may be required. A north-facing RAE or flexible nasotracheal tube is preferred. Care must be taken to fix the tracheal tube without exerting pressure on the nasal tip⁵⁹. A combination of 15° head-up positioning and modest hypotension using remifentanil or inhalational agents may be helpful in reducing bleeding, which can be significant. Damage to the tracheal tube can occur during the surgery⁶⁰. Rarely, surgery may result in severe bradycardia^{59  ,61}.

Temporomandibular joint (TMJ) ankylosis usually presents in the young child with limited mouth opening (Figure 19.2), and who has feeding difficulties which result in the child failing to thrive. Common aetiology includes trauma, congenital diseases, septic arthritis, and juvenile rheumatoid arthritis. The resultant ankylosis at the TMJ can lead to failure of the mandible to grow leading to micrognathia. Surgical management involves releasing the TMJ and if there is micrognathia, mandibular augmentation either with a costochondral graft or by the use of a distraction device (Figure 19.3). Mandibular distraction has been shown to improve the airway and many children can subsequently manage without a tracheostomy⁶².

Anaesthesia for TMJ ankylosis in these children can be challenging:

Costchondral grafts are used to augment the mandible as the presence of a joint interface allows ongoing growth in the grafted site and the augmented mandible will grow. Isolated pieces of rib are used as a simple graft to the jaw particularly if a part of the mandible has been removed due to benign or malignant tumour. The rib is joined to the mandible using plates and screws. When harvesting the graft, the surgeons will use a lateral incision in the anterolateral chest. If two ribs are needed, alternate ribs are used to minimize the risk of subsequent chest wall abnormality. Retrieval of these grafts is well tolerated. The risk that the pleura may be breached is managed by a ‘bubble test’ once the rib has been dissected out. The wound is filled with saline and a Valsalva manoeuvre performed to see if there is any leak of bubbles. If there is no breach of pleura a chest drain is not used. However, a postoperative chest X-ray is mandatory to confirm that there is no pneumothorax.

In addition to the routine analgesia for the facial surgery, the chest wound is infiltrated with a bolus of local anaesthetic. A surgically placed fine bore catheter, such as an epidural catheter, is placed in the subcutaneous space used to deliver continuous local anaesthetic using a syringe pump. Care is taken to ensure the dose of local anaesthetic is suitable for the size of the child. In practice a dose of 2–4 ml/hour of 0.25% levobupivacaine is sufficient when used in children above 20 kg.

Other donor sites for bone include the bone obtained from splitting pieces of skull during craniofacial remodelling, and the anterior iliac crest.

An area affected with abnormal blood vessels always poses additional risks for anaesthesia. Sturge–Weber malformation is a capillary haemangioma affecting the face and deeper tissues including the brain. Oral tracheal tubes are preferred and bleeding anticipated if extraction is to be performed in an affected area. Facial tumours are rare. Biopsy is a minor procedure but excision can be challenging. The relevant factors are the same as discussed in the section on major surgery of the jaw.

Craniosynostosis results from premature fusion of one or more cranial sutures. Syndromic craniofacial dysostosis is a familial form of craniosynostosis in which there is sutural involvement of the cranium and the mid-face resulting in specific clinical features⁶⁴. The common craniofacial conditions (Crouzon, Apert, and Pfeiffer) and the implications for anaesthesia are summarized in Table 19.4.

Reconstructive surgery of the cranium and the midface involves several sequentially phased procedures, which coincides with the craniofacial growth pattern and psychosocial development⁶⁴. Maxillofacial surgeons have a major role with coordinated input from the neurosurgical, plastics, ENT, ophthalmologic, and orthodontic teams.

Frontocranial remodelling is undertaken in infancy (8–11 months) to expand the anterior cranial fossa, to allow brain growth and to protect the eyes (proptosis). Advancement of midface hypoplasia is undertaken in the young child between 4–6 years of age. Orthognathic surgery is undertaken in the young adult around 14–16 years of age.

Children for major craniofacial surgery are usually admitted for a week of formal preoperative assessment by a multidisciplinary team that includes anaesthetists, ENT, ophthalmologic, speech and language development, as well as the various surgical and nursing teams.

Raised intracranial pressure is a feature of some syndromes. If a ventriculoperitoneal shunt is present, it is checked to ensure that it is functioning well. If there is a substantial cranial component to the surgery then the potential for venous air embolism should be borne in mind.

Vascular access can be difficult, particularly as some syndromes are associated with limb abnormalities. For major surgery, in addition to good peripheral venous access, arterial and central venous lines are used. The central line is preferably placed in the femoral vein as this is further from the surgical site and less likely to be compromised during neck movement during surgery.

Blood loss can be extensive. It is not unusual to replace one to two blood volumes³. About 20–50% of blood volume may be lost during craniosynostosis surgery⁷⁰. Therefore, it is important to plan ahead, obtain full blood count (FBC), clotting screen, correct any abnormalities, and cross match blood preoperatively.

It is important to ensure good positioning, a head-up tilt, with no obstruction to venous drainage of the head and avoid any hypertension. Provided the intracranial pressure is normal, modest hypotensive anaesthesia is useful to reduce intraoperative blood loss.

Blood conservation strategies inclusive of preoperative erythropoietin administration and autologous blood donation have been successfully used to minimize the need for allogenic blood transfusion⁷¹. However these strategies are not widely available.

Assessment of blood loss is very difficult and reliance has to be based upon clinical parameters and regular point of care testing of haemoglobin and blood gases¹⁵. A dilutional coagulopathy must be treated early.

Intraoperative acute normovolaemic haemodilution and blood salvage have not been shown to be effective in decreasing the allogenic blood transfusion requirements^{70  –72}. Intraoperative fluids are made up of routine maintenance fluids and replacement of surgical losses.

The aims are to improve the cosmetic appearance, dental occlusion, and the upper airway volume.

Le Fort III osteotomy corrects moderate midface hypoplasia involving the nose, zygoma, and bony orbits and is performed in young adults when skeletal maturation is complete⁷³. Recent advances include miniplate and screw fixation of osteotomy sites. This prevents the need for intermaxillary fixation and the associated problems⁵⁸. Monobloc osteotomy is done to advance the orbits and the midface as one unit (Table 19.5). Facial bipartition osteotomy, done in hypertelorism, allows three-dimensional correction of maxilla and orbits at the same time⁷⁴. This is major surgery associated with significant morbidity including substantial blood loss, postoperative intensive care, donor site morbidity, and occasionally, respiratory distress requiring tracheostomy^{73  ,75}.

Recently, distraction osteogenesis, a technique of mechanically-induced growth of new bone and soft tissue, has been applied to midface advancement. This technique allows for greater mobilizations over a period of time, does not require bone grafting, and is associated with low operative and postoperative morbidity⁷³.

A second surgical procedure is required to remove the device. The presence of an external maxillary distraction device, although looking rather daunting does not pose as much difficulty as expected. The vertical bar can be removed to allow unobstructed direct laryngoscopy. It is important to train the personnel and have the appropriate screwdrivers and wire cutters to remove the vertical bar should a postoperative problem occur⁷⁶. If a difficult direct laryngoscopy is anticipated, elective fibreoptic intubation is preferred for removal of maxillary distraction devices⁶⁹.

Children are nursed in a high dependency unit postoperatively where general and neurosurgical observations can be made. Local swelling can be extensive and patients are nursed with their head elevated and given prophylactic dexamethasone. Analgesia is achieved with local infiltration, simple analgesics, and a postoperative morphine infusion. Postoperatively maintenance fluids are restricted to 75% of normal. Blood and colloid replacement (including fresh frozen plasma [FFP] and platelets) is targeted to maintain a haemoglobin concentration above 10 g/dl. Hypovolaemia is common and fluid management needs to be closely monitored.

Imaging is very important in the planning phase of surgery. Careful assessment of the airway is key here. A baby can have computed tomography (CT) or magnetic resonance imaging (MRI) scans during normal sleep, but it is often difficult for children under about 8 years, or those who have learning difficulties to cooperate and remain still during these investigations. Sedation should be tried first as many children will be scanned successfully⁷⁷; however, if the child's airway is precarious then sedation is contraindicated.

CT scans are quick but an MRI will take more than 45 minutes and the MRI scanner is an unfriendly environment. The child will need to be anaesthetized or sedated depending on their age and ability to cooperate, in order to acquire good quality images⁷⁸. For those who need an anaesthetic, spontaneous respiration using a LMA is satisfactory in most children, even if they are syndromal. However, some children will have marked limitation of mouth opening and placement of LMA is not possible. These high-risk patients require tracheal intubation for an MRI scan.

A short frenulum is sometimes a cause of compromised speech or feeding difficulty. Division of the tie is a procedure done mainly in infants. This is a quick procedure and does not usually require intubation. A LMA or use of a nasal mask is sufficient. The frenulum is first injected with local anaesthetic, a clip applied across it to leave an avascular crushed area, and this is cut. Feeding is established soon after surgery and simple oral analgesia is sufficient.

The maxillofacial team is required to manage dental extraction in children with cleft or craniofacial conditions and in those with unusual medical conditions. Teeth can be buried in unexpected places deep within the palate or in the cleft. Whilst the surgery can take much longer than simple extractions, the principles of management are the same: the provision of a stable, patent airway and minimal interference with the surgical field. A nasotracheal tube with throat pack is preferred. Contraindications to nasal intubation include history of epistaxis, coagulopathy, narrow nasal passages (e.g. previous cleft repair, first arch syndromes), previous pharyngoplasty, previous trauma to the nose, and a deviated septum. A flexible LMA can be used for some of these cases and indeed is very useful for minor surgery.

Dental blocks are avoided by some as there is a concern that children are more likely to bite their lip and also do not like the numb feeling associated with the block. Local infiltration is satisfactory and well tolerated.

This is common in childhood and is secondary to dental infection. Trismus may be present but is unusual. If the infection has spread to the submasseteric area, then the resultant trismus may not relax on induction of anaesthesia and intubation will be difficult (see Chapter 11). A nasal fibreoptic intubation is the method of choice. In superficial infection, the trismus is more likely to relax on induction.

This is usually associated with use of phenytoin although can be associated with some rare syndromes such as juvenile hyaline fibromatosis. The soft tissue overgrowth can be so severe as to require gingivectomy. This is done with cautery to upper and lower gingivae so exposing the teeth. A nasal tracheal tube is required and intubation may be difficult due to poor access to the mouth. Fibreoptic intubation may be indicated⁷⁹. The airway management is much improved following surgery. Postoperative pain can be severe and may require intravenous morphine.

Tumours of the salivary glands are rare in children. Chronic infection particularly related to chronic aspiration may lead to abscess formation but the most common reason for surgery is for excess drooling in a child with cerebral palsy. Children with excess drooling are premedicated with atropine or glycopyrolate. A nasal tube is preferred as it remains out of the surgical site. A throat pack is essential. Bleeding is not marked and simple analgesics and local infiltration is sufficient for postoperative pain management.

Macroglossia may be congenital as in Beckwith–Weidemann syndrome or acquired as in hypothyroidism. Macroglossia can cause airway obstruction and affect development of jaws. Laser tongue reduction has replaced ‘excision with suturing’ for macroglossia.

Airway management is based on the severity of macroglossia. Anaesthesia induction may result in early airway obstruction, which is relieved using an oral or nasopharyngeal airway. A nasotracheal tube is used⁴⁰. Direct laryngoscopy is usually uneventful. However, fibreoptic techniques or occasionally tracheostomy may be required perioperatively⁸⁰. Postoperative complications include bleeding and swelling of the tongue with potential for airway obstruction. Postoperative fluids will be required until oral feeding is established and careful use of intravenous morphine may be necessary for analgesia.

Soft tissue facial trauma is a common indication for surgery. Aetiologies include road traffic accidents, falls, cycling, sporting injuries, or dental trauma. The possibility that an injury may be non-accidental should be kept in mind. If concerns are raised then local policies will guide the anaesthetist to liaise with the child protection lead, in their hospital⁸¹.

Following head injuries or polytrauma, children will be managed on a paediatric ICU. Facial fractures are repaired once the acute head injury has been stabilized and any serious injuries treated. Lacerations will need urgent attention. Paediatric orbital fractures which present with bradycardia need urgent treatment as this indicates local entrapment of the inferior rectus muscle in the orbital floor fracture. Delayed treatment can result in permanent muscle and eye mobility problems. Reducing the local pressure will relieve the symptoms of the occulocardiac reflex. Anaesthetic implications are similar to that required for major facial surgery. Nasal tracheal tubes are preferred but not essential if contraindicated by the clinical situation.

Small children requiring anaesthesia for any surgery are challenging and risks are much greater in patients undergoing major reconstructive surgery. The expertise of the paediatric anaesthetist and the perioperative care of the paediatric nursing and medical teams are required in managing babies and young children.