Neuromuscular Disorders
Volume 16, Issue 3 , Pages 210-219, March 2006

Muscular Dystrophy Campaign Funded Workshop on Management of Scoliosis in Duchenne Muscular Dystrophy 24 January 2005, London, UK

  • Francesco Muntoni

      Affiliations

    • The Dubowitz Neuromuscular Centre, Hammersmith Hospital, Imperial College, W12 ONN London, UK
    • Corresponding Author InformationCorresponding author. Tel.: +4420 8746 2187; fax: +4420 8383 3148
    • ,
  • Kate Bushby

      Affiliations

    • The Dubowitz Neuromuscular Centre, Hammersmith Hospital, Imperial College, W12 ONN London, UK
    • ,
  • Adnan Y. Manzur

      Affiliations

    • The Institute of Human Genetics, International Centre for Life, University of Newcastle-Upon-Tyne, UK

Received 21 December 2005

Article Outline

 

Twenty-three professionals from UK (Anaesthetists and Intensivists; Geneticists; Orthopedic and Spinal Surgeons; Orthotists; Paediatricians; Paediatric Neurologists; Physiotherapists; Respiratory physicians), one patient representative and one member of the sponsoring charity Muscular Dystrophy Campaign (MDC), attended a 1 day workshop in London, aimed at discussing the management of scoliosis in Duchenne muscular dystrophy (DMD). The full list of the participants, representing the largest UK neuromuscular centres and muscle clinics, is enclosed at the end of the report.

The aims of the workshop were:

1.Provide expert review of the subject

2.Consider and grade available evidence

3.Prepare minimum management guidelines for scoliosis surgery in neuromuscular patients (and in DMD in particular) to be used in the UK

4.To identify which existing NHS resources could manage minimum recommendations

5.Identify areas in which there is no good evidence or data available for definitive guidelines, and produce a pragmatic guide on current ‘good practice’ and suggestions for future studies.

The context of this workshop was laid out in a UK questionnaire based study funded by the MDC led by Peter Baxter (Sheffield), who is involved in carrying out a Cochrane review of the subject. The questionnaires were targeted at 746 boys with DMD over 10 years and their families. Two hundred and thirty four replies were received and 189 analysed. The boys reflected the general range and characteristics of the national DMD population in terms of age and physical ability. There was a clear progression of scoliosis with age across the teenage years, however, the practice in terms of offering surgery varied between centres. Out of the patients responding, 65 had had surgery, with a median inpatient stay of 14 days and median time of school of 6 weeks. Most of the patients who had had surgery were happy with their management, but many had had only verbal information with no written backup. Planning for post-operative management was not always optimal. Overall there was satisfaction with the outcome of surgery, with most families saying they would recommend it for other people. There was a noted improvement in posture post-operatively, but feeding and hoisting was often more difficult in the post-operative period.

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1. Literature review 

The literature on this subject consists mainly of retrospective cohort studies, and care is required with their interpretation in the light of the developments in surgical techniques over the years, in particular improvement in the instrumentation and reduction in operating time and peri-operative blood loss. Changes in the natural history of DMD due to improvements in management including the treatment of respiratory and cardiac insufficiency, the use of callipers, and the use of corticosteroids to improve muscle strength and prolong ambulation have altered the context for surgery, as people with DMD now can be expected to survive into adult life. In addition, prolongation of ambulation into the middle and even late teen has been associated in at least one study to marked decrease in the incidence of scoliosis [1]. Nonetheless, review of the relevant literature was performed and this was followed by expert group discussion.

1.1. Natural history of scoliosis in DMD 

Dr Adnan Manzur presented a detailed review of the relevant literature.

Spinal deformity in Duchenne muscular dystrophy comprises mainly of scoliosis, but may include additional components of kyphosis, rotation, hyperlordosis and there may be associated pelvic obliquity. This review focuses mainly on scoliosis as it is the clinically significant deformity, with propensity to rapid progression, and the associated morbidity. Kyphosis, hyperlordosis, or pelvic obliquity, are commented upon if they are considered to have a positive or negative impact on development or progression of scoliosis.

Scoliosis is the lateral curvature of the spine in the coronal plane. Scoliosis may be observed clinically on inspection, and is most often measured on antero-posterior radiographs, measured in degrees of Cobb angle. Some authors have defined scoliosis as the lateral curvature of spine in the coronal plane with a Cobb angle measuring more than 10°. Other imaging modalities documenting scoliosis include CT and MRI, but these have not been commonly used in assessment of scoliosis in Duchenne muscular dystrophy in previous literature. Past cohort or cross-sectional studies in Duchenne muscular dystrophy often did not define scoliosis: the terms ‘clinically significant scoliosis,’ ‘rapid progression,’ ‘collapsing spine’ have been used, but often not defined precisely. Many studies do not describe whether the spinal radiographs were obtained in the standing, sitting or lying position, and these omissions lead to some difficulty in comparison of the past studies. When should a spinal curvature be termed scoliosis? Some authors have defined scoliosis as the lateral curvature of spine in the coronal plane with a Cobb angle measuring more than 10° [2], [3].

Table 1 summarises the data from the studies documenting the natural history of scoliosis in Duchenne muscular dystrophy, with special reference to the incidence, severity and progression of scoliosis.

Table 1. Studies defining incidence or progression of scoliosis
StudyStudy sample characteristicsn=scoliosis/total numberIncidence of scoliosisCurve characteristicsTiming of onsetTiming of progressionCobb angle progression per month
Rideau 1984‘Typical and severe’ DMD, followed till death10/10100%
Cambridge 1987DMD patients who serial radiographs82/8695%Progressed to mean Cobb angle 75°Late ambulatory
Smith 198951 boys with no spinal surgery and followed till death51/198 Curve remained >20° while ambulant‘Rapid collapse’ begins 1 to 2 years of loss of walking2°
Brooke 1989120 DMD boys over the age of 11 years89/12074% Before loss of ambulation in majority
Oda 199346/96 patients selected, in whom adequate medical records and serial radiographs were available46/ Scoliosis + Kyphosis 46%) Unremitting progression
Kyphotic and Lordotic Variable
Scoliosis alone (15%) No progression. Cobb angle >30°
Hsu 1983 8/ Progression in all 0.3–4.5°
Seeager 1984 24/ Progression to 75° 1°
Rodillo 198993 DMD boys who had been rehabilitated in long leg callipers at loss of independent ambulation. 20 walked in orthoses beyond 13 years.84/93 Sharp rise in Cobb angle at 13 years, in those who stopped walking

Scoliosis was reported to be invariable in a cohort of 51 DMD who were followed till death [4]. Cambridge [5] documented a 95% incidence of ‘progressive scoliosis’ in 86 patients. Galasko [6], [7], quoted the incidence of scoliosis to be over 90%. The paper of Rideau et al. (1984) is often quoted to suggest that scoliosis is always present in DMD patients followed long-term, or till death [8]. On critical review of the Rideau paper, he recognised three different clinical categories of severity in DMD patients depending on the vital capacity, and described 10 patients in the severe categories who were followed till death and all of them developed scoliosis. Importantly, this paper does not report the incidence or severity of scoliosis in the milder DMD category [8].

Brooke [9] presented data on a large cohort of 293 boys with Duchenne muscular dystrophy: after age 11, 89 of 120 patients developed a scoliosis. Of note, ‘almost 25% of the patients had a relatively straight back (<10°) by the end of the study.’ Oda [10] reported 46 boys with Duchenne muscular dystrophy, 15% of which showed a scoliosis with no progression and eventual Cobb angles of <30°. We specially wished to highlight this group of patients which may form up to 25% of non-ambulant boys who either do not develop scoliosis, or the Cobb angle of their scoliosis remains <30°. We propose this to be considered as a clinically non-significant scoliosis.

The most common pattern of spinal deformity in non-ambulant boys with Duchenne muscular dystrophy is scoliosis with associated kyphosis [10]. This pattern of spinal deformity is at the greatest risk of rapid progression.

Though the onset of spinal asymmetry/scoliosis may occur in the late ambulant stages, significant progression while still ambulant, is unusual. Brooke [9] in particular documented that while the onset of spinal asymmetry occurred before loss of ambulation in the majority of a cohort or 89 boys with scoliosis, none of the ambulant children had a severe curvature. In another study, Smith [4] stated that the Cobb angle remained <20° in 51 boys while they remained ambulant. Rapid progression of scoliosis, also described as ‘rapid collapse’ was noted to begin 1–2 years after lost of walking [4]. Rodillo et al. [11] reported 84 boys who had been rehabilitated in long leg callipers at the time of loss of ambulation, and later developed scoliosis: in the boys who stopped walking in callipers before 13 years of age, there was a sharp rise in Cobb angle at and after age 13 years. The rapid progression of scoliosis therefore appears to be most importantly related to the age at loss of walking ability, and this often corresponds to the period of rapid growth spurt in adolescent boys.

Progression of scoliosis as measured in increase in Cobb angle per month is reported at between 1 and 4.5° [12], [13].

The factors modifying progression of scoliosis in Duchenne muscular dystrophy include prolongation of walking in long leg callipers [11] and prolongation of walking with the use of glucocorticoid corticosteroids [1]. The use of Deflazacort in 30 boys with Duchenne muscular dystrophy was reported to prolong walking ability to a mean age of 12.3 years (±2.7), and only 5 of these 30 patients developed a scoliosis with Cobb angle of more than 20° on follow-up to a mean age of 16 years [1]. In another recent series, 30 boys with Duchenne dystrophy were treated with prednisolone or deflazacort and followed up to the mean age of 14.6 years; only three of these 30 patients developed scoliosis for which surgery was indicated, during the study period [14]. This contrasts with the 68% incidence of significant scoliosis in the 19 boys (10 operated, three refused surgery) not treated with corticosteroids who were followed up contemporaneously, for a similar follow-up period, by Balban et al. and were considered a control group for their report [14]. The mechanism of prevention (or delay) of scoliosis by glucocorticosteroid therapy appears to be the prolongation of ambulation and there may also be a contribution from improved truncal muscle power [1].

The quality of life of surgically untreated patients with Duchenne muscular dystrophy with scoliosis of Cobb angle of <30° has not been reported, and in particular has not been compared with the quality of life and seating posture of operated patients.

The natural history of scoliosis in a large series of DMD patients has been very recently reported by Kinali et al. [15]. These authors reported 10-year experience of scoliosis management in 123 DMD, >17 years. Scoliosis was absent in 10%, and mild, non-progressive (<30°) in 13% of patients. Another 13% had moderate scoliosis (30°–50°) and were managed conservatively. Surgery was considered in 57% (70/123) with scoliosis >50° and eventually performed in 35%. The remaining either refused surgery (9%) or were unfit due to cardiorespiratory compromise (13%). In further 7% scoliosis (>50°), first noted after 14 years, was progressing slowly and surgery was not performed. At 17 years there was no difference in survival, respiratory impairment and sitting comfort amongst patients managed conservatively or with surgery. One third (44/123) of patients were managed satisfactorily without receiving spinal surgery [15].

1.2. Inter-relationship between scoliosis and respiratory function in DMD 

Dr Anita Simonds (London) reviewed the literature relative to this subject. None of the reported studies was randomised; the reports were typically series reports and pre and post-surgery natural history of scoliosis in DMD.

McDonald reported a series of 162 DMD patients followed over a period of 10 years [16]. Of these patients, 50% developed scoliosis between the age of 12–15, without any clear relationship between the age of loss of independent ambulation and the onset of scoliosis. These authors reported a progressive decline in predicted forced vital capacity (FVC%) that was slower between the age of 7–10 years (0.3% annually), compared to the rapid decline between 10–20 years (8.5%). The slope decreased again after the age of 20%, with an annual decline of 6.2% of FVC%. According to these authors the spinal deformity did not have a significant additional effect of age related decline in pulmonary function, and scoliosis did not contribute independently to mortality. However, patients with scoliosis had higher frequency of pulmonary complications than those without (39 vs. 14%)

Another large series of DMD patients (86) was reported by Yamashita et al. [17]. These authors tried to correlate scoliosis progression and respiratory function to type of scoliosis in DMD. Four groups (according to Oda's classification) were considered: (a) type 1, unremittent progression of scoliosis with kyphosis; (b) type 2, transition from kyphosis to lordosis before 15 years; (c) type 3, less deformity without longitudinal changes; (d) no scoliosis. A correlation between the severity and type of scoliosis and progression of respiratory dysfunction was found. Rapid and severe progression occurred in those with a VC plateau of <1900mls, and in those in whom plateau VC occurred before the age of 14 years. Amongst other studies that focused on the relationship between scoliosis and respiratory decline, Kurz et al. noticed that each 1 year of age and 10 of scoliosis decreased FCV by 4% [18]; Hsu et al. also correlated this to the severity of the curve and noted that in DMD with curvatures>of 40, the VC diminished by 12–16% each year [12].

Rideau suggested that FVC rather than scoliosis itself was a predictor of mortality and in particular that VC plateau of >1700mls was associated with less spinal deformity and longer survival [8].

Regarding the correlation between spinal surgery and its effect on respiratory function, one study of Galasko et al. (1995) concluded that a significant deterioration in lung function in DMD is secondary to the scoliosis and that patients who underwent spinal stabilisation maintained a significantly better lung function and had an improved survival compared with the patients who refused surgery [6]. These data were generated by a retrospective analysis of 181 DMD patients to whom spinal surgery was offered if scoliosis was 20° or more. The authors first noticed that standing slowed down the progression of scoliosis in non-ambulant children with DMD. Forty-eight of these 181 boys underwent spinal surgery, while 28 or those who were fit for surgery and offered the intervention, refused. When the two groups were compared and matched for FVC, age and muscle weakness, the operated group had a slower decline in respiratory function (stabilisation for 36 months, as opposed the 8% FVC annual decline in the non-operated group) and better long-term survival.

Contrary to these data however, a number of studies failed to report a significant effect of surgical intervention on respiratory function in DMD, In particular, Miller et al. [19], Kennedy et al. [20] and Granata et al. [21] failed to see any significant effect of scoliosis surgery on respiratory function and long-term survival, while improvement in sitting comfort, appearance or both was reported.

1.3. Peri-operative anaesthetic risks and their management in DMD 

Dr Geraldine Edge (Stanmore Hospital) reviewed the literature focused on the anaesthesia and associated complications for patients with DMD. She reviewed the relevant literature regarding the selection of patients (lung and cardiac function); the anaesthetic/surgical effect on lung function/the type of anaesthetic and complications. Dr Edge stressed that several independent risk factors co-exist in DMD, making an accurate pre-surgical assessment essential. These factors include adverse reactions to anaesthetic agents, large blood loss, prolonged ITU admission, temporary or permanent tracheotomies, respiratory infection and ventilator dependency. Patients are also frequently in a poor state of health at the time of the surgery, especially if feeding difficulties or frequent chest infections are present.

Regarding the selection of anaesthetic, it was stressed that there is no consistent anaesthetic regime which has been proven to be entirely safe for patients with DMD. A well-known complication to general anaesthetic in DMD is acute rabdomyolisis followed by hyperkalemia and cardiac arrest. This reaction has some similarities to malignant hyperthermia (especially in terms of triggering agents, including halogenate ethers, halotane and succinylcoline). However, at variance with malignant hyperthermia, it is not accompanied by muscle stiffness and does not respond to the administration of dantrolene. Anaesthetic agents that have an acceptable safe profile in DMD are nitrous oxide, propofol, opiates, barbiturates, ketamine and non-depolarising muscle relaxant, such as pancuronium/ vecuronium and atracurium.

Regarding the blood loss, several studies have suggested that patients with DMD tend to bleed more during surgery than do patients with other conditions, including patients with other neuromuscular conditions such as with spinal muscular atrophy undergoing the same or similar procedure [22], [23], [24]. Significant contributors to the blood loss in DMD is duration of surgery and the extent of the fixation, and in particular if the pelvis is fixed or not. The main theory to account for the increase blood loss of DMD children is related to the fact that DMD boys lack dystrophin in all muscle types, including smooth muscle; the excessive blood loss may therefore be related to a poor vascular smooth muscle vaso-constrictive response.

The excessive bleeding tendency and the duration of surgery are two very potent ‘stess’ factors that can compound morbidity in these patients. The choice of instrumental technique that can minimize the duration of surgery to the shortest possible time was highlighted as this eventually determines the severity of the bleeding.

Regarding the respiratory compromise, traditionally patients with poor FVC (below 30–40%) were not offered scoliosis surgery because of the unacceptably high risk of surgery. In addition, early spinal fusion is advocated by many authors, as by the time the curve is greater than 35°, the FVC is almost always <40% PFVC. More recent data suggest however, that spinal surgery can be performed also in DMD patients with a FVC between 20 and 30% with a similar safety profile to the one performed in patients with FVC>30% [25], [26]. However, this requires a highly specialized team and an established collaboration with a respiratory unit with expertise in the management of non-invasive ventilation. Indeed some of these patients might already be onto mask ventilation prior to surgery, but even if not they will most likely require non-invasive ventilation to be performed after the surgery. In a recent series on DMD patients with low (<30%) FVC, all the spinal fusions were performed by experienced spinal surgeons; all patients were anaesthetized by one of four consultant anaesthetists, all of whom have considerable experience in the field of paediatric ‘syndromal’ anaesthesia [25], [26]. Post-operatively, the patients were managed on an intensive care unit and, as their dependency decreased, on a high dependency unit, until they were off all ventilatory support. The nursing and physiotherapy staff were all experienced in the care of both disabled patients and in cough enhancement techniques, including exsufflator–insufflator.

1.4. Cardiac complications following scoliosis surgery in DMD 

Dr Ros Quinlivan (Oswestry) reviewed and summarized the relevant publications. She reported that overt cardiac failure is rare and is a terminal event in 10–20% DMD [27], [28], although in rare cases severe and even fatal cardiac involvement has been reported also during the first decade of life [29]. Pathological studies of large series of patients documented myocardial fibrosis in over 90% of cases by 20 years affecting more severely the posterobasal and lateral wall of the left ventricle, while both the right ventricle and atria are minimally affected.

ECG is a very sensitive test to identify cardiac compromise and indeed ECG abnormalities are common in DMD all ages [30]. Although complex ventricular ectopic beats increase with advancing age and correlate with LV dysfunction [31], [32], the more common ECG changes only poorly correlate with left ventricular dysfunction and this limits the yield of ECG. Echocardiography is the most commonly used tool to study cardiac dysfunction in DMD. The first abnormalities detected are infero-basal wall motion abnormalities, followed by left ventricular dilatation. Early sign of cardiac involvement as detected by echo can sometime be already detected in the first 10 years of life; it is present in 30% of cases aged 14 years and in 100% of cases>the age of 18 [33]. LV dysfunction is considered a powerful predictor of mortality [34].

Other powerful investigations techniques exists, such as radionuclide imaging (SPECT), [28]; PET [35], [32]; tissue Doppler exist but while they clearly are able to identify abnormalities significantly earlier than echo [36], no prognostic data is available. Regarding determination of serum hormones, both cardiac Troponin and atrial natriuretic peptide and brain natriuretic peptide are elevated only in the late phases of heart failure, when echocardiography is clearly abnormal [37], [38], [39]. The determination of these hormones therefore does not provide additional advantage compared to echocardiography.

A few papers have been published regarding cardiomyopathy complicating spinal fusion. Granata et al. [21] reviewed the literature published in the period 1980–1994. Of 160 DMD cases reported in the literature, there were three deaths of which two during surgery and one the day after, all attributable to cardiomyopathy. In one case reported by the author (as part of an internal audit, Granata also reported one cardiac death at day 5 post-surgery in a child who had had normal echo and a FVC of 87% of predicted values. A particular stress that was identified in this case was a significant peri-operative blood loss.

Adding together the published data and unpublished audits from different units in 359 cases, the risk of peri-operative hypovolaemic cardiac arrest was 3.4% and not always correlated with abnormal echocardiography; the cumulative risk of cardiac death was 1.4%.

1.5. Impact of bracing on scoliosis in DMD 

Michelle Eagle (Newcastle) reviewed the literature regarding spinal bracing and progression of scoliosis. She reported that there currently is no evidence that bracing reduces the rate of progression of the scoliosis. On the contrary several authors have commented on its progression despite bracing [5], [7], [8], [9], [12], [13], [40], [41]. A few authors have however, reported on an effect of wearing a brace on slowing down the progression of the scoliosis [40]; and others have commented on the effect that rigid spinal bracing may have on reducing an already compromised VC [42], [43]. Most published work therefore suggests that the primary indication of bracing is that on postural control and comfort of sitting rather than control of progression of the scoliosis.

1.6. Effect of different types of surgical intervention on outcome 

Brad Williamson and Imelda Hughes (Manchester) reviewed the relevant literature.

Regarding the type of instrumentation, Gaine et al. [44] reported recently a series of 74 patients 55 of whom were operated using the Luque procedure; and 19 the Isola procedure. The overall outcome is that Isola gave better immediate correction, although this was not statistically significant (possibly because of the relative small number of patients in the second category). Long-term follow-up indicated again that the Isola system maintained a statistically significant better correction with time.

The level at which the spine should be fused is controversial. While there is little debate on the upper fusion level (usually T2), there clearly are different clinical practices related to the decision to fix the pelvis or limit the spinal fusion to L5. On the whole fixation of the pelvis is preferred by many spinal surgeons if there is a significant pre-operative pelvic tilt; or if there is concern that there could be progression of curvature below the level of fusion after several years. On the contrary other spinal surgeons believe that the long-term correction achieved with L5 fusion is equivalent to the one obtained including also the pelvis; but limiting the fusion to L5 shortens the operative time and the blood loss. The series reported are all retrospective, relatively small and at time combine series of patients in which different surgical instrumentation was used, and this is in itself might have influenced the outcome. It was discussed that the available published evidence does unequivocally allow to assign the superiority of one technique versus the other.

Mubarak et al. [45] reported 22 patients in whom Luque instrumentation were used. Twelve patients were instrumented to the sacropelvis, and 10 were instrumented to L5. Both patient groups had relatively minor curves and forced vital capacity >40%. Mean pre-operative and post-operative curves were nearly identical in both groups. The mild degree of trunk shift and pelvic obliquity was similar between the two groups.

Alman and Kim [46] reported 48 patients fused using sublaminar wires. In 38 cases the Cobb angle was <40° and pelvic obliquity <10 and these were fused to L5. Three of these 38 eventually had increased pelvic obliquity and two required revision procedures for worsening obliquity when their pulmonary function deteriorated to <25% of predicted values. This complication did not occur in any of the 10 patients in whom the pelvis was fused. The authors recommend fusion to the sacrum for scoliosis in Duchenne muscular dystrophy, especially for patients with an apex to their curve below L1.

Sengupta et al. [47] reported two series of patients operated at two different centres and compared the outcome. The first series comprised 31 patients who had fixation to the pelvis, using standard Luque instrumentation and pelvic fixation. The mean age at surgery in this group was 14, the mean Cobb angle 48° and pelvic obliquity 21°. Following surgery, the mean Cobb angle was 17° and the pelvic obliquity 7°. At final follow-up (mean 4.6 years post-surgery) correction was essentially maintained, Cobb angle 22° and pelvic obliquity 12°. In the second group, 19 cases had fixation to L5 using pedicle screws in the lumbar spine and sublaminar wires in the thoracic spine. These patients were on the whole younger and had a less severe scoliosis compared to patients in the former group: the mean age was 11.7 years, and mean Cobb angle of 20° and a pelvic obliquity of seven before the operation. Following surgery, the correction was to 3.2° (Cobb angle) and 2.2° (PO) immediately after surgery, and 5.2° and 2.9° at the final follow-up (mean 3.5 years), respectively. The mean estimated blood loss and mean hospital stay and complications were lower in the group of patients fused to L5 compared to those fused to the pelvis.

Regarding general complications of the surgical procedure, the most common include wound infection (ranging from 4 to 20%; [9], [44]; hardware failure (ranging from 4% in Gaine et al. to 10% in Ramirez et al.[48]). Prolonged post-operative ventilation is not unusual, with for example, 16% of patients requiring ventilation for more than 5 days [49] (Miller et al.); rare cases might require temporary tracheotomy (1/48 in Galasko et al. [7]; 2/30 in Marsh et al. [26]).

A common post-surgical complaint is difficulty in feeding following surgery. For example, all cases in Miller series all 17 cases could feed independently before surgery with only 6/16 able to do so post-operatively [50]. Of these, six developed adaptive means of feeding, two used arm supports and two remained dependent for feeding. Bridwell described 13/33 boys were dependent for feeding after surgery all having being independent before [51]. This can have an effect on nutrition; in a series from Iannacone et al. 60% of boys who gained weight in the 12 months following surgery were independent eaters while 78% of boys who lost >5% body weight in the 12 months after surgery were dependent eaters [52].

Neurological complications are uncommon; thigh pain and paresthesia occurred in 2/30 in Ramirez series [48]; 1/7 temporo sacral nerve root dys-saesthesia; 1/25 transient neuogenic bladder [53]. Skin ulcerations have been documented in 1/30 cases in Ramirez et al. [48]; 1/68 in Miller et al. [19]; 1/30 in Granata et al. [21] has been reported.

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2. Consensus statements 

2.1. Is spinal surgery viable in DMD? 

There are many years of experience and published case series confirming that spinal surgery is a safe and effective way to manage progressive scoliosis in DMD when it is carried out in experienced centres with multidisciplinary support. Mortality and complication rates in experienced centres and in patients managed by multidisciplinary teams are low and satisfaction levels high.

2.2. What is the aim of spinal surgery in DMD? 

The primary aim of spinal surgery in DMD is to correct scoliosis and prevent further progression of spinal deformity. Long-term objectives of the surgery are to achieve a good sitting posture, comfort and quality of life by avoiding the complications of progressive scoliosis.

2.3. What is the optimum surveillance for the development of scoliosis in DMD? 

Between 75 and 90% of children with DMD develop a scoliosis and when present this has a significant tendency to progress. Awareness of scoliosis as an issue in DMD is needed both for the medical team and for the families even in the ambulant phase (when scoliosis is however, unlikely to be clinically significant). A multidisciplinary approach involving the paediatrician/paediatric neurologists, orthopaedic surgeons are essential. The muscle clinic team should monitor for the development of scoliosis in all children with DMD before and after loss of independent ambulation. When there is a clinically detectable scoliosis sitting X-rays, usually every 6 months, are indicated under the guidance of the team who will be responsible for the management of the scoliosis.

2.4. When should surgery be considered? 

This depends on several factors (degree of spinal curvature, respiratory function and cardiac status). The decision on when to perform surgery should be taken in partnership with the whole multidisciplinary team, the affected boy and his family.

With respect to the spinal curve, there are three main variables—Cobb angle, progression and flexibility of the spine. Pubertal growth spurt plays an essential role as rapid progression is most likely during this period. Progression of scoliosis is less of an issue after skeletal maturity is achieved.

From a surgical perspective, the best time for surgery is likely to be when there is a progressive deterioration but the curve is still flexible. The optimum range of Cobb angle for the decision process to perform surgery is likely to be around 20–40°. Forced vital capacity falls during the teenage years in DMD. Scoliosis surgery should optimally be performed when respiratory reserve is not too compromised (FVC>30). However, FVC below 30% is not an absolute contraindication to surgery and has been done safely in patients with FVC between 20 and 30% as improved supportive care and peri-operative nasal mask ventilation in experienced hands may make surgery possible and the rate of complications not dissimilar from stronger patients. These patients need however, to be individually assessed by an experienced anaesthetists and respiratory physician as they clearly are more fragile compared to stronger patients.

A full pre-operative assessment is essential (within 3 months of surgery) and should include forced vital capacity, peak cough flow and overnight oximetry. In the presence of significant respiratory impairment, for example, if there is evidence of nocturnal hypoventilation or recurrent severe chest infections, then the patient should be familiarised with non-invasive ventilation and cough augmentation techniques before surgery as this may ameliorate post-operative recovery. The nutritional status of the patients should be carefully considered and caloric supplemented initiated, in patients who are failing to thrive, at least 6 months prior to surgery. Occasionally, a pre-spinal surgery gastrostomy might be required.

All patients with DMD are at risk of cardiomyopathy, though they are rarely symptomatic. The importance of cardiac status in DMD has become much better recognised in recent years. Existing guidelines recommend that cardiac status in DMD should be monitored every year from the age of 10 by echocardiography and ECG [54]. Assessment should in addition be performed within 3 months of surgery. It is already established that progressive abnormalities on echocardiography are an indication for treatment with ACE inhibition and beta blockade. Patients who have stabilised on such treatment should not represent an absolute contraindication to surgery, but such patients need to be considered and monitored carefully. Risks increase dramatically with fractional shortening of <25% and the benefits of surgery need to be balanced against the overall prognosis. Deteriorating cardiac failure on treatment is a poor prognostic factor irrespective of surgery.

It is important to recognise that cardiac problems may develop during the stress of surgery even with normal pre-operative assessment. Significant stress factors that are known to be associated with increased peri-operative morbidity are the duration of surgery and the amount of blood loss. All efforts should therefore be put in trying to reduce both the operative time and blood loss.

2.5. Is there a role for spinal bracing in the management of scoliosis in DMD? 

Spinal bracing is part of the total postural management of the child which includes the provision of appropriate wheelchair seating. There is no evidence that spinal bracing treats or slows the progression of scoliosis. Bracing can improve posture and comfort in sitting in patients in whom spinal surgery is contraindicated or refused. Comfortable seating in tilt in space chairs with appropriate adjustment for change in posture following surgery is an essential part of the process of planning for and rehabilitation following surgery so local physiotherapy, seating and wheelchair services should be involved in the planning process.

2.6. Who should be performing scoliosis surgery in patients with DMD? 

Detailed guidelines for summarising the requirements for individual centres involved in scoliosis surgery have been published (BOA guidelines 2001, http://www.boa.ac.uk/BSS/) and have been recently subjected to significance revisions to take into account the complexity of this procedure in a high-risk population such as patients with neuromuscular diseases (BOA guidelines in preparation). Surgeons operating on patients with DMD and other paediatric neuromuscular diseases should be working with all members of the neuromuscular multidisciplinary team and have regular experience in operating on this patient group.

2.7. Is there a consensus on what kind of surgery should be performed? 

The choice of surgical intervention depends on the clinical indication in an individual case. The more recent instrumentation systems have an advantage compared to the previous Luque or Harrington rods technique and should therefore be preferred.

Regarding the issue of fixation to the pelvis, there are significant variations in the clinical practice of individual centres. In many centres were surgery is performed very early on minimal or mild curvatures, the choice is that of not fixing the pelvis and in most instances medium term follow-up indicates that this choice is correct. In centres or cases in which the scoliosis is more significant, and there is significant (20° or more) pelvic obliquity present at the time of surgery, fixation to the pelvis is indicated. Longer term follow-up data are needed on functional and postural results of these different approaches.

2.8. How are patients and their families best prepared for surgery? 

Pre-operative issues that need to be addressed should include an assessment of the impact of surgery on seating, housing, hoisting, mobility, school and other functional issues. There needs to be a full exploration with the patient of the best and worst possible outcomes, and where possible a chance to see the unit and the intensive therapy unit prior to admission. Written information should be available to the patient and the family. The MDC has produced two information leaflets, a general one on scoliosis and a more recent one on surgical management of scoliosis. Both are available at the MDC website: http://www.muscular-dystrophy.org/information_resources/factsheets/medical_issues_factsheets/surgical.html. Generation of more condition specific literature may also be appropriate in the future.

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Acknowledgements 

This workshop was made possible by the generous contribution of the Muscular Dystrophy Campaign of Great Britain and Northern Ireland. The authors wish to thank all the colleagues, the patient and charity representative for their contribution to this workshop and to the preparation of this report.

List of participants:

1.Peter Baxter, Consultant Pediatric Neurologist, Sheffield

2.Rob Bullock, Consultant Anesthesist, Newcastle

3.Kate Bushby, Consultant Geneticists, Newcastle

4.Nicky Courtier, Pediatric Physiotherapist, London

5.Michelle Eagle, Pediatric Physiotherapist, Newcastle

6.Geraldine Edge, Consultant Anesthesist, Stanmore

7.Ruth Geall, MDC Representative

8.Mike Gibson, Consultant Orthopedic Surgeon, Newcastle

9.Kay Hawkins, Consultant Intensivist, Manchester

10.Imelda Hughes, Consultant Pediatric Neurologist, Manchester

11.Ian Lefkoski, Consultant Spinal Surgeon, Stanmore

12.Jonathan Lucas, Consultant Orthopedic and Spinal Surgeon, London

13.Francesco Muntoni, Consultant Pediatric Neurologist, London

14.Marion Main, Pediatric Physiotherapist, London

15.Adnan Manzur, Consultant Pediatric Neurologist, London

16.Samuel Mildon, Patient representative, London

17.Mr Hilali Nordeen, Consultant Orthopedic and Spinal Surgeon, London

18.John O'Dowd, Consultant Spinal Surgeon, London

19.Dav Patel, Consultant Anesthesist, Manchester

20.Colin Peacock, Orthotist, Newcastle

21.Steve Porter, Orthotist, London

22.Ros Quinlivan, Consultant Pediatrician, Oswestry

23.Anita Simonds, Consultant Respiratory Physician, London

24.Brad Williamson, Consultant Orthopedic Surgeon, Manchester

25.Elisabeth Wraige, Pediatric Neurologist, London

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PII: S0960-8966(06)00006-X

doi:10.1016/j.nmd.2006.01.004

Neuromuscular Disorders
Volume 16, Issue 3 , Pages 210-219, March 2006

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