Duchenne muscular dystrophy (DMD) is a genetically determined disorder characterised by ongoing degeneration of skeletal muscle with subsequent reorganisation by fatty infiltration. The prevalence of the disorder is estimated to be approximately one in 3500 male births. The onset of clinical symptoms usually occurs during early childhood and progression of the disease leads to loss of ambulation in late childhood. At present, there is no cure for DMD and treatment is aimed at symptom minimisation. In many patients, corrective orthopaedic procedures under general anaesthesia are performed either to prolong patients’ ambulation or to improve quality of life at a late stage of the disease. Various anaesthesia-related specific perioperative risks in DMD patients are well recognised. Complications such as rhabdomyolysis, hyperkalaemic cardiac arrest and intraoperative and postoperative hyperthermia have been reported in the past.1–6 The relevant question is whether developments and changes in anaesthetic techniques over recent years have improved the safety of anaesthesia in this special group of patients. In addition, uncertainty exists regarding the frequency of complications during anaesthesia because information is based predominantly on case reports or small series of patients.
The aim of this study was to document current practice and the incidence of anaesthesia-related severe complications in a series of DMD patients scheduled for various corrective orthopaedic procedures under general anaesthesia. We hypothesised that a retrospective analysis of our cases may provide useful information to assist the development of clinical guidelines.
Ethical approval for this study was provided by the Ethical Committee of Erlangen University Hospital, Erlangen, Germany (Chairperson Professor P. Betz) by correspondence from December 2011. We undertook a retrospective case review study of DMD patients who had undergone general anaesthesia for orthopaedic surgery. The period covered by the survey was from April 2000 to December 2008. Our institutional computerised record system codes the diagnoses of all patients seen. Charts were reviewed for preoperative, intraoperative and postoperative data. Data collected included biometric data, age at which the patient was diagnosed with DMD and age at which the patient became wheelchair-bound (where applicable). Preoperative ECG, echocardiography, pulmonary function tests and total creatinine kinase concentration were also recorded.
At our institution, general anaesthesia for patients with DMD is based on intravenous agents; no volatile anaesthetic drugs are used. The use of opioids and non-depolarising muscle relaxants depends on the type and duration of surgical procedure and is left to the discretion of the anaesthetist. In patients in whom a muscle relaxant is used, monitoring of muscle relaxation is performed by acceleromyography. In patients undergoing spinal fusion surgery, tranexamic acid, cell saver and a forced air warmer are used routinely. All patients who undergo spinal fusion surgery are provided with postoperative ventilatory support for as long as it is necessary.
On the basis of the anaesthetic record of each patient, the anaesthetic technique used, duration of anaesthesia, type and duration of surgery, estimated intraoperative blood loss, perioperative auto-transfusion and transfusion of blood and blood products were noted. In addition, the records were reviewed for the following perioperative events: duration of postoperative ventilatory support (denoted as time from end of surgery to tracheal tube removal) and duration of stay in the post-anaesthesia care unit or ICU. Any problems or adverse events specified by the anaesthetist were documented.
Data analysis was carried out with SPSS version 14.0 (SPSS Inc., Chicago, Illinois, USA). Basic descriptive statistics, including mean, range and percentages, were calculated for the demographic and anaesthetic data. Correlations between data were computed with Spearman's rank test. A P value of less than 0.05 was considered significant.
A total of 191 DMD patients who had undergone 232 episodes of general anaesthesia were identified. No DMD patient was excluded from our review. Depending on the type of surgical intervention performed, the patients were divided into two groups. Our series included 153 anaesthetic procedures for surgery of the lower extremity (group A) and 79 anaesthetic procedures for corrective spinal fusion (group B). In all, 137 of the 191 patients (72%) had undergone one or more anaesthetic before the diagnosis of DMD had been verified. Medical history revealed cardiac arrest with successful resuscitation in two patients during general anaesthesia prior to the diagnosis of DMD and prior to the study period.
The biophysical and demographic data of the study population are shown in Table 1. As expected, patients scheduled for spinal fusion were older compared with patients scheduled for lower extremity surgery. Table 2 shows the results of preoperative tests. Preoperative pulmonary function tests showed an overall reduced vital capacity among the older patients belonging to group B. One patient of this group was receiving non-invasive nocturnal home ventilation preoperatively. Preoperative cardiac evaluation revealed pathological ECG findings in 11 patients in group A (7%) and in 17 patients in group B (22%). Eight patients presented with early dilated cardiomyopathy and the others showed early diverse valvular insufficiencies.
For premedication, a weight-based dose of midazolam was given to 132 of 153 (86%) patients in group A and to 18 of 79 (23%) in group B. Propofol was used as the standard intravenous anaesthetic agent for induction and maintenance of anaesthesia in all patients. Nitrous oxide was used in 108 of 153 (78%) patients in group A and in 27 of 79 (34%) in group B. Volatile anaesthetic agents were not used. The most commonly used medication for analgesia was fentanyl and the most frequently used muscle relaxant was rocuronium. The frequency and variety of anaesthetic drugs used are shown in Table 3. In group A, a laryngeal mask airway was used in 63 patients. Overall, there were eight documented difficult direct laryngoscopies (Cormack classification III or IV).7 In three patients in group B, the tracheal tube could be inserted only with the aid of an endoscope.
Estimated blood loss and volumes of transfused blood and blood products are summarised in Table 4. The median estimated blood loss in group B was 3000 ml. An average of 942 ml of cell-saver blood was re-transfused. Blood and blood products were transfused only in group B. Postoperative haemoglobin, creatinine kinase and serum potassium concentrations are summarised in Table 4. Preoperative and postoperative creatinine kinase and potassium concentrations were similar in both groups. In group B, the postoperative serum creatinine concentration was below the normal range (Table 4). The average temperature at the end of surgery is shown in Table 4. The highest temperature noted in the records was 36.3°C in group A and 36.5°C in group B. No hyperthermia was documented. In all patients in group A, the tracheal tube or laryngeal mask was removed at the end of surgery. In contrast, all patients in group B required postoperative invasive ventilatory support for an average of 19 h (Table 4). There was no significant correlation between preoperative pulmonary function tests and the duration of postoperative artificial ventilation. In two patients in group B, tracheostomy was performed 2 weeks after surgery in order to provide prolonged ventilatory support. Two other patients in group B required non-invasive daytime and night-time ventilation via face mask.
Progress in medical management of DMD has resulted in longer survival and DMD patients now require more frequent corrective surgical procedures to improve their quality of life. Our large series documents anaesthesia for typical orthopaedic procedures undertaken at different stages of the disease.
Development of chronic respiratory insufficiency in DMD is a known finding, indicating increasing weakness of respiratory muscles, particularly loss of diaphragmatic strength. Additionally, the developing scoliosis in nearly all older DMD patients impairs pulmonary reserve.8 In our series, this development is reflected by a reduced vital capacity which is more obvious in older patients (Table 2). The finding of reduced vital capacity confirms data from other investigations.4,9,10
Another known common problem in longstanding DMD is cardiac involvement caused by dystrophin deficiency. In our study, eight patients presented with cardiomyopathy, a comparatively low incidence.11,12 However, another 20 patients showed different types of valvular insufficiencies, a finding which is often the first symptom of dilated cardiomyopathy. Recent investigations have provided evidence of genetic linkage of cardiomyopathy to DMD.13–15 Although acute heart failure has been described during major surgical procedures in patients with DMD,5,16 no cardiac complications were documented in our series. We were not able to evaluate retrospectively the significance of diagnosed respiratory or cardiac involvement in predicting perioperative complications in DMD.
The small number of patients pre-medicated in the two groups reflects our cautious use of preoperative medication in DMD patients. At our institution, patients with reduced respiratory reserve due to obvious muscle weakness receive no sedative preoperative medication in order to avoid any additional impairment of respiratory function.
In all DMD patients, general anaesthesia was induced and maintained with propofol titrated to effect. Because the total amount of propofol given was not documented, we cannot present individual-related dose requirements of propofol as previously published.17 Since the first published report of its administration in DMD,18 propofol has been used in DMD without major adverse effects. To date, propofol has not been associated with the occurrence of rhabdomyolysis or unexplained fever in DMD. These two fatal complications in DMD patients have been reported repeatedly over the years in association with the use of nearly all volatile anaesthetics including halothane, isoflurane, sevoflurane and desflurane.2–6,19–25 These case reports demonstrate that, despite the avoidance of succinylcholine, DMD patients exposed to volatile anaesthetics may develop perioperative rhabdomyolysis or unexplained fever. Therefore, in accordance with other authors, we strictly avoid any inhalational volatile anaesthetics in DMD and use only vapour-free anaesthesia machines.26
Our medical records revealed an overall rate of 4% of difficult direct laryngoscopy. When the occurrence of difficult direct laryngoscopy is considered within the groups, it is clear that the incidence is higher in the older patients in group B (about 7.5%). This incidence is obviously higher than that in normal patients undergoing routine general surgery.27 Difficult direct laryngoscopy in DMD has not been reported frequently in the literature.28,29 Surprisingly high was the documented use of the fibre-optic endoscope to insert a tracheal tube in patients in group B (nearly 4%). This high incidence of difficult intubation is in agreement with another retrospective review documenting complications performing tracheostomy in DMD patients at an advanced stage of the disease.30 One explanation could be the fact that patients with longstanding DMD frequently present with obesity, a large tongue, restricted mouth opening and limited mobility of the cervical spine. All these signs are recognised risk factors for difficult direct laryngoscopy and intubation.
The use of muscle relaxants is a major concern when performing anaesthesia in DMD patients. Pharmacological muscle relaxation is not absolutely necessary in every case. The administration of non-depolarising neuromuscular blocking agents in DMD requires consideration of some special aspects. Several prospective investigations have shown that nearly all commonly used non-depolarising neuromuscular blocking agents can be used in DMD. This is especially true for rocuronium31,32 and mivacurium.33 These reports have also documented that the response to non-depolarising neuromuscular blocking agents is altered in DMD. The most striking difference is a delayed onset of blockade in DMD compared with normal patients.31,32 This effect should be kept in mind in situations when rapid airway protection is necessary. Another significant difference is a prolonged duration of recovery from neuromuscular block in DMD following standard doses of non-depolarising neuromuscular blocking agents.31–34 Furthermore, these effects depend on the stage of the disease, with more pronounced effects with ongoing progression.35 This altered response to non-depolarising neuromuscular blocking agents in DMD makes it necessary to assess complete neuromuscular recovery by quantitative measurement, such as acceleromyography. Pyridostigmine has been demonstrated to be an effective reversal agent in DMD.36 Many reports of fatal hyperkalaemic cardiac arrest in association with the use of succinylcholine in DMD have raised anaesthetists’ awareness of this potential complication. Therefore, it is now commonly accepted by the anaesthesia community that this drug should be strictly avoided in DMD.26 Two patients in our series have had a cardiac arrest with successful resuscitation during earlier anaesthesia before a diagnosis of DMD had been made. Although we had no further information about anaesthesia, we speculate that succinylcholine may have been given. In both patients, anaesthesia was carried out in our centre avoiding succinylcholine and inhalational anaesthetics, without any adverse events.
As in other patients, the analgesic drugs of choice in DMD are opioids. Depending on the duration of surgical intervention, the choice of opioids should be based on the pharmacological effect and pharmacokinetics. We have administered nearly all clinically used opioids in our series (Table 3).
The most serious documented complication during anaesthesia was extensive blood loss in patients undergoing corrective surgery of the spine. The documented median blood loss of about 3000 ml during spinal surgery corresponds to published data from other groups,9 or seems smaller.37 We suggest that the routine use of prophylactic anti-fibrinolytics and devices for intraoperative auto-transfusion have reduced the need for homologous blood transfusion during these procedures. On average, only two units of homologous packed red blood cells were given during spinal fusion surgery in our series. Clotting factors and fibrinogen had been provided by early transfusion of fresh frozen plasma. The early transfusion of clotting factors during spinal surgery in DMD seems to be necessary because impaired haemostatic function has been reported during spinal surgery in DMD.37
Postoperative average temperature at the end of surgery in the spinal fusion group was lower than normal. This finding is not surprising. Perioperative temperature management during spinal fusion surgery in children is a known problem.38 Despite the use of a forced air warmer, not all patients had a normal temperature at the end of surgery.
The requirement for prolonged postoperative ventilatory support was relevant only after spinal surgery. In all patients who underwent lower extremity surgery, the laryngeal mask or tracheal tube was removed at the end of surgery, irrespective of the use of non-depolarising neuromuscular blocking agents. In our opinion, two factors are responsible for this difference between the groups: the overall better general physical status of patients undergoing lower extremity surgery and the smaller extent of peripheral surgical intervention. In contrast, after spinal surgery, all patients required postoperative artificial ventilation of different durations. In our series, we could not establish a significant correlation between preoperative vital capacity and duration of postoperative ventilatory support. Data from our review do not confirm previous investigations in which such an association had been reported.9,39 Spinal stabilisation surgery in DMD cannot improve respiratory muscle strength. However, spinal surgery and additional (daytime or nocturnal) non-invasive ventilation may improve quality of life.40
Our case series has all the typical limitations of retrospective studies based on medical records. There is always the possibility of poorly documented minor complications or minor adverse events caused by anaesthetic medication. However, our large series without major anaesthesia-related complications shows that our anaesthetic management may be used safely in DMD.
In conclusion, we have presented our experience of anaesthetic management for 232 orthopaedic interventions in 191 patients suffering from different stages of DMD. There was no major anaesthesia-associated complication in our series and, most importantly, no case of rhabdomyolysis or cardiac arrest. The most serious problems documented were difficult direct laryngoscopy, especially in patients at an advanced stage of the disease and extensive blood loss during spinal stabilisation surgery. The result of our case series confirms our opinion that the strict avoidance of succinylcholine and volatile anaesthetics during anaesthesia in DMD can prevent known anaesthetic hazards such as rhabdomyolysis or hypercalcaemia.
Assistance with the study: none declared.
Sources of funding: Financial support was provided solely from departmental sources.
Conflicts of interest: none declared.
1. Breucking E, Reimnitz P, Schara U, Mortier W. Anesthetic complications
. The incidence of severe anesthetic complications
in patients and families with progressive muscular dystrophy
of the Duchenne and Becker types. Anaesthesist
2. Larsen UT, Juhl B, Hein-Sorensen O, de Fine Olivarius B. Complications
in patients with Duchenne's muscular dystrophy
(a retrospective study). Can J Anaesth
3. Miller ED Jr, Sanders DB, Rowlingson JC, et al. Anesthesia-induced rhabdomyolysis in a patient with Duchenne's muscular dystrophy
4. Saint-Maurice C, Egu JF, Gaudiche O, et al. Anesthesia in patients with Duchenne muscular dystrophy
. Ann Fr Anesth Reanim
5. Sethna NF, Rockoff MA, Worthen HM, Rosnow JM. Anesthesia-related complications
in children with Duchenne muscular dystrophy
6. Smith CL, Bush GH. Anaesthesia
and progressive muscular dystrophy
. Br J Anaesth
7. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia
8. Beck J, Weinberg J, Hamnegard CH, et al. Diaphragmatic function in advanced Duchenne muscular dystrophy
. Neuromuscul Disord
9. Harper CM, Ambler G, Edge G. The prognostic value of preoperative predicted forced vital capacity in corrective spinal surgery for Duchenne's muscular dystrophy
10. Shapiro F, Sethna N, Colan S, et al. Spinal fusion in Duchenne muscular dystrophy
: a multidisciplinary approach. Muscle Nerve
11. Hoffman EP, Brown RH Jr, Kunkel LM. Dystrophin: the protein product of the Duchenne muscular dystrophy
12. Nigro G, Comi LI, Politano L, Bain RJ. The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy
. Int J Cardiol
13. Coral-Vazquez R, Cohn RD, Moore SA, et al. Disruption of the sarcoglycan-sarcospan complex in vascular smooth muscle: a novel mechanism for cardiomyopathy and muscular dystrophy
14. Towbin JA, Hejtmancik JF, Brink P, et al. X-linked dilated cardiomyopathy. Molecular genetic evidence of linkage to the Duchenne muscular dystrophy
(dystrophin) gene at the Xp21 locus. Circulation
15. Melacini P, Fanin M, Danieli GA, et al. Myocardial involvement is very frequent among patients affected with subclinical Becker's muscular dystrophy
16. Schmidt GN, Burmeister MA, Lilje C, et al. Acute heart failure during spinal surgery in a boy with Duchenne muscular dystrophy
. Br J Anaesth
17. Fairfield MC. Increased propofol requirements in a child with Duchenne muscular dystrophy
18. Ginsburg RS, Porterfield K, Lippmann M. Propofol: bolus induction plus continuous infusion in a patient with Duchenne muscular dystrophy
19. Boltshauser E, Steinmann B, Meyer A, Jerusalem F. Anaesthesia
-induced rhabdomyolysis in Duchenne muscular dystrophy
. Br J Anaesth
20. Chalkiadis GA, Branch KG. Cardiac arrest after isoflurane anaesthesia
in a patient with Duchenne's muscular dystrophy
21. Girshin M, Mukherjee J, Clowney R, et al. The postoperative cardiovascular arrest of a 5-year-old male: an initial presentation of Duchenne's muscular dystrophy
. Paediatr Anaesth
22. Obata R, Yasumi Y, Suzuki A, et al. Rhabdomyolysis in association with Duchenne's muscular dystrophy
. Can J Anaesth
23. Sethna NF, Rockoff MA. Cardiac arrest following inhalation induction of anaesthesia
in a child with Duchenne's muscular dystrophy
. Can Anaesth Soc J
24. Smelt WL. Cardiac arrest during desflurane anaesthesia
in a patient with Duchenne's muscular dystrophy
. Acta Anaesthesiol Scand
25. Takahashi H, Shimokawa M, Sha K, et al. Sevoflurane can induce rhabdomyolysis in Duchenne's muscular dystrophy
26. Gurnaney H, Brown A, Litman RS. Malignant hyperthermia and muscular dystrophies. Anesth Analg
27. Williams KN, Carli F, Cormack RS. Unexpected, difficult laryngoscopy: a prospective survey in routine general surgery. Br J Anaesth
28. Jones D, Cone A. Management of a difficult airway in a patient with Duchenne's muscular dystrophy
. Br J Hosp Med
29. van Stralen D, Perkin RM. Retrograde intubation difficulty in an 18-year-old muscular dystrophy
patient. Am J Emerg Med
30. Orlikowski D, Prigent H, Gonzales-Bermejo J, et al. Noninvasive ventilation as an alternative to endotracheal intubation during tracheotomy in advanced neuromuscular disease. Respir Care
31. Muenster T, Schmidt J, Wick S, et al. Rocuronium 0.3 mg x kg-1 (ED95) induces a normal peak effect but an altered time course of neuromuscular block in patients with Duchenne's muscular dystrophy
. Paediatr Anaesth
32. Wick S, Muenster T, Schmidt J, et al. Onset and duration of rocuronium-induced neuromuscular blockade in patients with Duchenne muscular dystrophy
33. Schmidt J, Muenster T, Wick S, et al. Onset and duration of mivacurium-induced neuromuscular block in patients with Duchenne muscular dystrophy
. Br J Anaesth
34. Ririe DG, Shapiro F, Sethna NF. The response of patients with Duchenne's muscular dystrophy
to neuromuscular blockade with vecuronium. Anesthesiology
35. Ihmsen H, Schmidt J, Schwilden H, et al. Influence of disease progression on the neuromuscular blocking effect of mivacurium in children and adolescents with Duchenne muscular dystrophy
36. Muenster T, Forst J, Goerlitz P, Schmitt HJ. Reversal of rocuronium-induced neuromuscular blockade by pyridostigmine in patients with Duchenne muscular dystrophy
. Paediatr Anaesth
37. Turturro F, Rocca B, Gumina S, et al. Impaired primary hemostasis with normal platelet function in Duchenne muscular dystrophy
during highly-invasive spinal surgery. Neuromuscul Disord
38. Murat I, Berniere J, Constant I. Evaluation of the efficacy of a forced-air warmer (Bair Hugger) during spinal surgery in children. J Clin Anesth
39. Milne B, Rosales JK. Anaesthetic considerations in patients with muscular dystrophy
undergoing spinal fusion and Harrington rod insertion. Can Anaesth Soc J
40. Eagle M, Bourke J, Bullock R, et al. Managing Duchenne muscular dystrophy
: the additive effect of spinal surgery and home nocturnal ventilation in improving survival. Neuromuscul Disord