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DISCUSSION Herniation through an iliac crest defect was first reported by Oldfield in 1945.1 The actual incidence of herniation at the site of an iliac crest bone graft donor site is not known; however, some studies have suggested an incidence of up to 5% of cases.2 As demonstrated by the three cases in the present report, the consequences of such hernias can be severe, particularly if strangulation occurs. Hernia formation appears to be related to the size of the defect and to whether a full-thickness graft has been taken.3 It has been advocated that taking a full-thickness graft should be avoided, with preservation of the iliac crest.4 Once a bone graft has been taken, reconstruction of the region should be undertaken, with suturing of the periosteum, fascial layers and muscular insertions. The elderly, obese and those with poor muscular development are at increased risk of developing incisional hernia and special care should be taken when these patients require bone graft harvesting. It has been suggested that using either the anterior or posterior parts of the iliac crest is less likely to develop hernia than if the middle part is used for the bone graft.3 In high-risk patients, primary closure using mesh may reduce the incidence of subsequent hernia development.3

Diagnosis of hernia through iliac crest defects is generally obvious, but may be more difficult in the obese patient unless the diagnosis is suspected. Plain X-ray will show the bony defect and a CT scan may show the defect and its contents. Patients with a history of iliac crest bone graft harvesting who present with abdominal pains should be suspected of having an incarcerated incisional hernia. The three cases presented demonstrate some of the different ways incisional hernia through the iliac crest may present and some of the potential consequences as a result of incarceration.

REFERENCES 1. Oldfield MC. Iliac hernia after bone grafting. Lancet 1945; i: 810–12. 2. Auleda J, Bianchi A, Tibau R, Rodriguez-Cano O. Hernia through iliac crest defects. Int. Orthop. 1995; 19: 367–9. 3. Hamond MM, Majeed SA. Incisional hernia at iliac crest defects. Arch. Orthop. Trauma Surg. 1989; 108: 383–5. 4. Edmonson AS. Surgical techniques. In: Edmonson AS, Cremshaw AH (eds). Campbells Operative Orthopaedics, 6th edn. St Louis: Mosby, 1980; 24–7.

ANZ J. Surg. 2002; 72: 157–158

CASE REPORT

AIRWAY FIRE DURING FORMATION OF TRACHEOSTOMY T. J. WHEATLEY AND G. J. MADDERN University of Adelaide, Department of Surgery, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia Key words: airway fire, tracheostomy. Abbreviations: ENT, ear, nose and throat; SSD, silver sulfadiazine.

INTRODUCTION Fire during tracheostomy formation is a rare but serious complication. Reports of such a complication have been published in ear, nose and throat (ENT) journals, and in anaesthetic journals,1–7 but not in general surgical journals. All surgeons who perform tracheostomy should be acquainted with the potential risk of fire during such a procedure.

CASE REPORT A 66-year-old man required formation of a tracheostomy as part of his intensive care treatment. He had been ventilated for 14 days after T. Wheatley FRCS; G. Maddern FRACS. Correspondence: Professor G. Maddern, The Department of Surgery, Level 6, The Queen Elizabeth Hospital, Woodville Road, Woodville, SA 5011, Australia. Email: [email protected] Accepted for publication 1 June 2001.

an emergency oesophagogastrectomy for a perforated oesophageal carcinoma and was being treated for ongoing sepsis. The tracheostomy procedure was performed under general anaesthesia and, just prior to the tracheal incision being made, the patient was ventilated with 100% oxygen as per normal practice. The tracheal incision was made using diathermy and just after the incision had been made a spark was noticed inside the trachea at the visible tip of the PVC endotracheal tube. With the next insufflation of 100% oxygen, this became a fire that vented directly upwards through the tracheostomy. The anaesthetist immediately disconnected the endotracheal tube from the oxygen supply and the fire was extinguished with saline by the surgical team. Once the fire was controlled, the endotracheal tube was replaced by a size 9.0 tracheostomy tube without incident. The removed endotracheal tube was observed to be burnt along the distal 2 cm. No change in monitored parameters occurred during this incident and the Spo2 immediately after insertion of the tracheostomy tube was recorded at 99%. An immediate flexible bronchoscopy was performed in theatre, which revealed a few soot particles distal to the tracheostomy site, but no burns or airway oedema. A plastic surgical opinion was sought regarding the

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burn wound, which appeared to be full thickness for a radius of 3 cm around the tracheostomy site. Daily dressings with silver sulfadiazine (SSD) paste were advised. Over the following 4 weeks, the burn wound healed over with conservative measures only; no skin graft was required. The patient’s subsequent stay in intensive care was complicated by other medical problems that kept him ventilated for a further 12 weeks. Once he was weaned from the ventilator and the tracheostomy tube removed, the stoma healed over within 2 weeks and has caused no subsequent problems.

DISCUSSION Fire during any surgical procedure is a rare, but potentially lethal, complication that not only endangers the patient, but also exposes the surgical and anaesthetic team to risk of injury. The procedure of tracheostomy provides an uncommon situation where the surgeon is operating in an environment where, for a period of time, the oxygen concentration is extremely high. Occasional reports of intraoperative fires during such procedures appear in anaesthetic and ENT journals;1–7 it is important that general surgeons, who often perform tracheostomies in hospitals where ENT surgeons do not, are as aware of this problem. Most reports of tracheostomy related fires have resulted in uneventful recoveries,1–6 but deaths have been recorded too.7 A previous report from this institution2 details how a fire needs three components to occur: (i) a combustible material; (ii) an oxidizing agent; and (iii) something to ignite it. The combustible material is usually the endotracheal tube, as in the case reported here. As described Table 1. Suggestions for the avoidance and management of tracheostomy related fires Avoidance Electrosurgical devices must be used with great care (if at all) during and after the trachea is opened; until the trachea is open, the high oxygen environment is contained to the airways and anaesthetic circuit Management Disconnect the oxygen supply immediately Leave the endotracheal tube in situ Extinguish the fire with water or something similar Complete the tracheostomy immediately (which should be possible at this stage) Perform bronchoscopy to document the condition of the distal airways Manage burns as appropriate

previously, PVC would not normally burn in an atmosphere that was less than 25% oxygen, but with the addition of oxidizing agent (100% oxygen in this case), PVC becomes a good fuel. The use of surgical electocautery devices is the usual source of ignition and this case was no exception. The use of diathermy to open the trachea is not unusual, but even if a scalpel is used, then electrocautery of bleeding vessels can have the same effect on the fuel–oxygen combination lying within the trachea. Once a fire has occurred, the tendency is for the flames to vent out of the tracheostomy site, along the path of least resistance to gas flow.1 This is fortunate because it diverts the fire from the airway and, thus, limits damage. Differing opinions have been voiced about whether or not to remove the endotracheal tube immediately, initial thoughts being that prompt removal prevents further burns.1–6 More recently, it has been pointed out that removing the tube in such a case may leave the airway unprotected and difficult to re-establish, especially if there is a problem with insertion of the tracheostomy tube.1,7 To summarize, the case reported here is very similar in nature and outcome to other reports. The combination of electrocautery, an oxygen-rich atmosphere and a potential fuel resulted in the rare occurrence of an intraoperative fire. Fortunately, the patient was not adversely affected by this event, but the potential for serious injury and/or death should be heeded. Suggestions for the avoidance and management of tracheostomy related fires are given in Table 1.

REFERENCES 1. Chee WK, Benumof JL. Airway fire during tracheostomy: Extubation may be contraindicated. Anesthesiology 1998; 89: 1576–8. 2. Lim HJ, Miller GM, Rainbird A. Airway fire during elective tracheostomy. Anaesth. Intens. Care 1997; 25: 150–2. 3. Thompson JW, Colin W, Snowden T, Hengesteg A, Stocks RM, Watson SP. Fire in the operating room during tracheostomy. South. Med. J. 1998; 91: 243–7. 4. Aly A, McIlwain M, Duncarage J. Electrosurgery-induced endotracheal tube ignition during tracheostomy. Ann. Otol. Rhinol. Laryngol. 1991; 100: 31–3. 5. Bailey MK, Bromley HR, Allison JG, Conroy JM, Krzyzaniak W. Electrosurgery-induced endotracheal tube ignition during tracheostomy. Anesth. Analg. 1990; 71: 702–4. 6. Simpson JI, Wolf GL. Endotracheal tube fire ignited by pharyngeal electrocautery. Anaesthesiology 1986; 65: 76–7. 7. Baur DA, Butler RC. Electro-cautery ignited endotracheal tube fire: Case report. Br. J. Oral Maxillofac. Surg. 1999; 37: 142–3.