The diagnosis and orthopaedic treatment of inherited muscular diseases of childhood

Segmental Pedicle Screw Instrumentation and Fusion Only to L5 in the Surgical Treatment of Flaccid Neuromuscular Scoliosis

STUDY DESIGN

A retrospective cohort study was performed.

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of stopping segmental pedicle screw instrumentation constructs at L5 in the treatment of neuromuscular scoliosis.

SUMMARY OF BACKGROUND DATA

Duchenne muscular dystrophy and spinal muscular atrophy are flaccid neuromuscular disorders in which gradual deterioration is the hallmark and have a lot of characteristics in common despite differences in etiology. Instrumentation and fusion to the sacrum/pelvis has been a mainstay in the surgical treatment of flaccid neuromuscular scoliosis and recommended to correct pelvic obliquity. However, the caudal extent of instrumentation and fusion in the surgical treatment of flaccid neuromuscular scoliosis has remained a matter of considerable debate and there have been few studies on the use of segmental pedicle screw instrumentation for flaccid neuromuscular scoliosis.

METHOD

From 2005 to 2007, a total of 27 consecutive patients with neuromuscular disorders (20 Duchenne muscular dystrophy and 7 spinal muscular atrophy), aged 11 to 17 years, underwent segmental pedicle screw instrumentation and fusion only to L5. Assessment was performed clinically and with radiologic measurements. Minimum 2-year follow-up was required for inclusion in this study.

RESULTS

Twenty patients were enrolled in this study. No patient was lost to follow-up. All patients had L5 tilt of less than 15° and a coronal curve with apex L2 or higher preoperatively. Preoperative coronal curve averaged 70° (range: 51°-88°), with a postoperative mean of 15° (range: 5°-25°) and 17° (range: 6°-27°) at the last follow-up. The pelvic obliquity improved from 15° (range: 9°-25°) preoperatively to 5° (range: 3°-8°) postoperatively and 6° (range: 3°-8°) at the last follow-up. The L5 tilt improved from 9° (range: 2°-14°) preoperatively to 2° (range: 0°-4°) postoperatively and 2° (range: 0°-5°) at the last follow-up. Physiologic sagittal plane alignment was recreated after surgery and maintained long-term. There was no significant loss of correction of coronal curve and pelvic obliquity. There was no major complication.

CONCLUSION

Segmental pedicle screw instrumentation and fusion to L5 was safe and effective in patients with flaccid neuromuscular scoliosis with apex L2 or higher and minimal L5 tilt of less than 15°. Segmental pedicle screw instrumentation ending at L5 offered the ability to correct spinal deformity and pelvic obliquity initially, intermediate and even long-term, with no major complications. This method in appropriate patients can be a viable alternative to instrumentation and fusion to the sacrum/pelvis in the surgical treatment of flaccid neuromuscular scoliosis.

LEVEL OF EVIDENCE

N/A.

Anesthetic management of 877 pediatric patients undergoing muscle biopsy for neuromuscular disorders: a 20-year review

BACKGROUND

The objectives are to review the anesthetic management and anesthetic-related adverse events in patients undergoing muscle biopsy for a broad spectrum of neuromuscular disorders (NMD).

AIM

The study aims to assess the hypothesis that perceived awareness of potential anesthesia-induced hyperkalemia and MH in patients with NMD reduces the frequency of such events.

METHODS

A 20-year retrospective review of 877 consecutive patients undergoing muscle biopsy to establish diagnoses of NMD has been performed. Patients were categorized prebiopsy into six groups: M (myopathy and muscular dystrophy), MM (mitochondrial or metabolic myopathy), N (neurodegenerative, peripheral neuropathy or spinal muscular atrophy disorder), D (dermatomyositis), C (cardiomyopathy), or S (seizure disorder). Data were collected for demographics, anesthetic management, pre- and postoperative anesthesia-induced muscle injury, postbiopsy histopathologic diagnosis, and concordance comparisons between pre- and postbiopsy diagnoses.

RESULTS

There were 513 males (58.5%) and 364 females (41.5%) (1.4:1) with 137 individuals (15.6%) operated on under 1 year of age and two-thirds by 6 years of age. NMD diagnosis was reached in 409 (46.6%) while 468 (53.4%) had no specific pathology. No patients exhibited signs of anesthesia-induced muscle injury (malignant hyperthermia, rhabdomyolysis, cardiac arrest, or postoperative deterioration of weakness). MM was the largest group pre biopsy (367, 41.8%). Anesthetic agents were: nitrous oxide in 657 (74.9%); volatile agents in 139 (15.8%); intravenous agents in 836 (95.3%) (primarily propofol, midazolam, and fentanyl); nondepolarizing muscle relaxants in 404 (46.1%); and regional anesthesia in 112 (12.8%) [most commonly spinal anesthesia in 80 (71.4%)]. Comparing preoperative diagnostic category with postoperative diagnosis, there was a concordance of 78% (319/409) between the two for cases with a definitive diagnosis and 89.7% (787/877) for all cases.

CONCLUSIONS

In this retrospective study, no patient exhibited signs or symptoms of hyperkalemia or MH probably because the incidence is very low and becomes even less likely due to the selection of the various anesthetic agents and strategies administered.

Scapular winging: an update

Scapular winging is a rare disorder often caused by neuromuscular imbalance in the scapulothoracic stabilizer muscles. Lesions of the long thoracic nerve and spinal accessory nerves are the most common cause. Numerous underlying etiologies have been described. Patients report diffuse neck, shoulder girdle, and upper back pain, which may be debilitating, associated with abduction and overhead activities. Accurate diagnosis and detection depend on appreciation of the scapulothoracic anatomy and a comprehensive physical examination. Although most cases resolve nonsurgically, surgical treatment of scapular winging has been met with success.

The natural history of cardiac and pulmonary function decline in patients with duchenne muscular dystrophy

STUDY DESIGN

Retrospective review of scoliosis progression, pulmonary and cardiac function in a series of patients with Duchenne Muscular Dystrophy (DMD).

OBJECTIVE

To determine whether operative treatment of scoliosis decreases the rate of pulmonary function loss in patients with DMD.

SUMMARY OF BACKGROUND DATA

It is generally accepted that surgical intervention should be undertaken in DMD scoliosis once curve sizes reach 35° to allow intervention before critical respiratory decline has occurred. There are conflicting reports, however, regarding the effect of scoliosis stabilization on the rate of pulmonary function decline when compared to nonoperative cohorts.

METHODS

We reviewed spinal radiographs, echocardiograms, and spirometry, hospital, and operative records of all patients seen at our tertiary referral center from July 1, 1992 to June 1, 2007. Data were recorded to Microsoft Excel (Microsoft, Redmond, WA) and analyzed with SAS (SAS Institute, Cary, NC) and R statistical processing software (www.r-project.org).

RESULTS

The percent predicted forced vital capacity (PPFVC) decreased 5% per year before operation. The mean PPFVC was 54% (SD = 21%) before operation with a mean postoperative PPFVC of 43% (SD = 14%). Surgical treatment was associated with a 12% decline in PPFVC independent of other treatment variables. PPFVC after operation declined at a rate of 1% per year and while this rate was lower, it was not significantly different than the rate of decline present before operation (P = 0.18). Cardiac function as measured by left ventricular fractional shortening declined at a rate of 1% per year with most individuals exhibiting a left ventricular fractional shortening rate of more than 30 before operation.

CONCLUSION

Operative treatment of scoliosis in DMD using the Luque Galveston method was associated with a reduction of forced vital capacity related to operation. The rate of pulmonary function decline after operation was not significantly reduced when compared with the rate of preoperative forced vital capacity decline.

Surgical correction of spinal deformity in patients with congenital muscular dystrophy

BACKGROUND

Congenital muscular dystrophy (CMD), among the myopathic disorders is one form of flaccid neuromuscular disorder (NMD). Patients with NMD frequently develop progressive spinal deformity. For NMD patients who have a severe spinal deformity, sitting is often difficult and is accompanied by pain and breakdown of the skin. Spinal deformity surgery in these patients has been highly effective in stabilizing the spine, maintaining upright, comfortable sitting balance, and improving patients' quality of life. However, many studies have reported significant rates of peri/postoperative complications in these patients. To our knowledge, there has been no study on the results of spinal deformity surgery in patients with CMD. The purpose of this study was to review the clinical and radiological results of spinal deformity surgery in this group of patients with CMD.

METHODS

Between 2004 and 2007, a total of 10 CMD patients underwent scoliosis surgery. There were three patients with Fukuyama CMD, three with Ullrich CMD, and 4 with nonsyndromic CMD (merosin-negative). They were nonambulatory. All the patients had standard posterior spinal fusion and pedicle-screw-alone fixation from T3 or T4 to L5 for spinal deformity. Our inclusion criteria required that each patient (1) had considerable difficulty with sitting balance and pain or breakdown of the skin due to scoliosis; (2) was able to ventilate his or her lung autonomously; (3) was not ventilator-dependent; and (4) did not have cardiac failure. Sufficient informed consent was important, and the decision to perform surgery was made by the patient/family with sufficient preoperative informed consent. Patients were trained with inspiratory muscle training (IMT) using an inspiratory muscle trainer (Threshold IMT) for 6 weeks prior to surgery Cardiac function was assessed preoperatively. Pulmonary function tests were performed preoperatively and postoperatively. Radiographic assessments were performed on sitting anteroposterior (AP) and lateral radiographs. These assessments were made periodically. The Cobb angles of the curves and spinal pelvic obliquity (SPO) on the coronal plane, thoracic kyphosis, and lumbar lordosis were measured. The preoperative AP radiograph and side-bending films were examined to determine flexibility. Patients' and parents' satisfaction were surveyed by a self-completed questionnaire at the last follow-up.

RESULTS

Percent forced vital capacity (%FVC) increased from a mean of 30% before IMT to a mean of 34% the day before surgery. The preoperative scoliosis was 75 degrees (range 61 degrees -95 degrees ). The scoliotic curvature on preoperative side-bending films was 19 degrees (range 11 degrees -28 degrees ). All patients were extubated on the day of surgery. No patients developed cardiac or respiratory complications. The scoliotic curvature was 18 degrees (range 10 degrees -25 degrees ) immediately after surgery, and 19 degrees (range 12 degrees -27 degrees ) at the last follow-up. The pelvic obliquity improved from a mean of 17 degrees (range 14 degrees -20 degrees ) preoperatively to a mean of 6 degrees (range 4 degrees -9 degrees ) postoperatively and to 7 degrees (range 4 degrees -10 degrees ) at the last follow-up. Balanced sitting posture was achieved and maintained. On the sagittal plane, good reconstruction of sagittal plane alignment was recreated and maintained. There were no major complications or deaths. All patients/parents completed the outcome satisfaction questionnaire. Eight patients/parents were very satisfied and two were satisfied.

CONCLUSIONS

Pedicle-screw-alone fixation and fusion to L5 was safe and effective in CMD patients with scoliosis of <95 degrees and pelvic obliquity of <20 degrees . Scoliosis curves were flexible (75% correction) on side-bending films preoperatively. Curve correction and maintenance of correction in the coronal and sagittal plane was excellent. The pelvic obliquity significantly improved. Balanced sitting posture was achieved and maintained in all patients. Our patients with CMD spinal deformity and a moderately and severely decreased FVC could be operated on safely and successfully with general anesthesia. All patients were extubated in the operating room. There were no major complications or deaths. We believe a FVC of <30% alone is not a predisposition to pulmonary complications. However, cardiomyopathy might be a determining risk of mortality, and we believe surgery for these patients should be avoided. Patients' and parents' satisfaction was high.

Can the caudal extent of fusion in the surgical treatment of scoliosis in Duchenne muscular dystrophy be stopped at lumbar 5?

Instrumentation and fusion to the sacrum/pelvis has been a mainstay in the surgical treatment of scoliosis in Duchenne muscular dystrophy (DMD) and is recommended to correct pelvic obliquity. The caudal extent of instrumentation and fusion in the surgical treatment of scoliosis in DMD has remained a matter of considerable debate, and there have been few studies on the use of segmental pedicle screw instrumentation for this pathology. From 2004 to 2007, a total of 28 patients with DMD underwent segmental pedicle screw instrumentation and fusion only to L5. Assessment was performed clinically and with radiologic measurements. All patients had a curve with the apex at L2 or higher preoperatively. Preoperative coronal curve averaged 74 degrees, with a postoperative mean of 14 degrees, and 17 degrees at the last follow-up. The pelvic obliquity improved from 17 degrees preoperatively to 6 degrees postoperatively, and 6 degrees at the last follow-up. Good sagittal plane alignment was recreated after surgery and maintained long term. In 23 patients with a preoperative L5 tilt of less than 15 degrees, the pelvic obliquity was effectively corrected to less than 10 degrees and maintained by adequately addressing spinal deformity, while five patients with a preoperative L5 tilt of more than 15 degrees had a postoperative pelvic obliquity of more than 15 degrees. Segmental pedicle screw instrumentation and fusion to L5 was effective and safe in patients with DMD scoliosis with a minimal L5 tilt (<15 degrees) and a curve with the apex at L2 or higher, both initially and long term, obviating the need for fixation to the sacrum/pelvis. Segmental pedicle screw instrumentation and fusion to L5 was safe and effective in patients with DMD scoliosis with stable L5/S1 articulation as evidenced by a minimal L5 tilt of less than 15 degrees, even though pelvic obliquity was significant. There was no major complication. With rigid segmental pedicle screw instrumentation, the caudal extent of fusion in the treatment of DMD scoliosis should be determined by the degree of L5 tilt. This method in appropriate patients can be a viable alternative to instrumentation and fusion to the sacrum/pelvis in the surgical treatment of DMD scoliosis.

Surgical management of severe scoliosis with high risk pulmonary dysfunction in Duchenne muscular dystrophy: patient function, quality of life and satisfaction

In a previous study, the authors reported the clinical and radiological results of Duchenne muscular dystrophy (DMD) scoliosis surgery in 14 patients with a low FVC of <30%. The purpose of this study was to determine if surgery improved function and QOL in these patients. Furthermore, the authors assessed the patients' and parents' satisfaction. %FVC increased in all patients after preoperative inspiratory muscle training. Scoliosis surgery in this group of patients presented no increased risk of major complications. All-screw constructions and fusion offered the ability to correct spinal deformity in the coronal and pelvic obliquity initially, intermediate and long-term. All patients were encouraged to continue inspiratory muscle training after surgery. The mean rate of %FVC decline after surgery was 3.6% per year. Most patients and parents believed scoliosis surgery improved their function, sitting balance and quality of life even though patients were at high risk for major complications. Their satisfaction was also high.

Surgical management of severe scoliosis with high-risk pulmonary dysfunction in Duchenne muscular dystrophy

Between 2005 and 2007, 14 patients who had severe scoliosis in Duchenne muscular dystrophy (DMD) and a poor forced vital capacity (FVC) of <30% at admission underwent scoliosis surgery. FVC on admission was 21.6% (range, 16-27%). The patients were given respiratory muscle training using a pulmonary trainer (Threshold IMT, Philips Respironics, Inc.) for six weeks before operation. FVC increased to 26.2% (range, 22-31%) the day before operation. The mean preoperative scoliosis was 98 degrees (range, 81 degrees-130 degrees). All patients underwent posterior fusion and all-screw construction and were extubated on the operative day. No patients developed any respiratory complications. The postoperative scoliosis was 34 degrees (range, 20 degrees-40 degrees) (65%). FVC remained stable at six weeks after operation. FVC decreased to 19.8% (range, 16-25%) and the mean scoliosis was 35 degrees (range, 23 degrees-40 degrees) (64%) at two years after operation. DMD patients with severe scoliosis and FVC considered too low to permit reasonable surgical risk could undergo surgery and could benefit from surgery.

Posterior spinal fusion for scoliosis in duchenne muscular dystrophy diminishes the rate of respiratory decline

STUDY DESIGN

To assess the rate of decline in pulmonary function in Duchenne muscular dystrophy (DMD) before and after posterior spinal fusion for scoliosis.

OBJECTIVE

To compare the rate of respiratory decline using percent normal forced vital capacity (%FVC) measurements before and after posterior spinal fusion.

SUMMARY OF BACKGROUND DATA

Posterior spinal fusion for scoliosis is used widely in DMD, although the long-term pulmonary effects have not been well established.

METHODS

Fifty-six patients were assessed. Percent forced vital capacity was the outcome parameter with data analysis using a mixed-model repeated-measures ANOVA and paired t tests. Group 1: Inclusion criteria were a diagnosis of DMD, 2 or more pulmonary function tests presurgery, and 2 or more postsurgery. Group 2: The rates of respiratory decline before and after spinal fusion for the whole study population were determined by within-subjects mixed-model regression analysis to account for the varying number of FVC studies between patients and unequal spacing between tests.

RESULTS

Group 1: 20 patients. Mean length of time of respiratory value determination was 2.5 +/- 1.0 years presurgery and 5.6 +/- 2.8 years postsurgery. Mean rate of decline presurgery was 8.0% +/- 4.1% per year, which decreased to 3.9% +/- 1.9% per year postsurgery (paired t test = 4.58, P < 0.0001). Group 2: 56 patients. The respiratory value determinations ranged from 4 years presurgery to 8 years postsurgery. The rates of respiratory decline based on the whole study population were 4% per year presurgery, which decreased to 1.75% per year postsurgery (F-test comparison of slopes = 19.71, P < 0.0001).

CONCLUSIONS

Posterior spinal fusion for scoliosis in DMD is associated with a significant decrease in the rate of respiratory decline postsurgery compared with presurgery rates.

Should foot surgery be performed for children with Duchenne muscular dystrophy?

The authors conducted a retrospective study to determine the outcome of foot surgery in full-time wheelchair users with Duchenne muscular dystrophy. Medical records on all 88 teenaged boys with Duchenne muscular dystrophy treated at the authors' institution were obtained and reviewed. Patients completed questions about shoe wear, pain, hypersensitivity, and cosmesis, and a foot examination was performed. There were no significant differences between patients who did and did not receive foot surgery with respect to shoe wear (P > 0.05), pain (P > 0.05), hypersensitivity (P > 0.05), or cosmesis (P > 0.05). Hindfoot motion was significantly better (P > 0.05) but equinus contracture was significantly worse (P > 0.05) in patients who had not had surgery.

A severe case of facioscapulohumeral muscular dystrophy (FSHD) with some uncommon clinical features and a short 4q35 fragment

Severe and early facioscapulohumeral muscular dystrophy (FSHD) is relatively rare. In this report, we describe a case of severe, infantile onset FSHD in a patient with asymmetric progressive ptosis and early hyperlordosis. DNA analysis revealed a very short 4q35 allele of 8.6 kb and a somatic mosaicism for the 4q35 deletion detected in a subclinically affected parent of the patient. This case demonstrates difficulties in the management of abnormal posture, especially early hyperlordosis in children with this disorder.

The effects of knee-ankle-foot orthoses in the treatment of Duchenne muscular dystrophy: review of the literature

OBJECTIVE

A systematic review of the available literature on the effectiveness of knee-ankle-foot orthoses in the treatment of Duchenne muscular dystrophy.

DESIGN

A computer search was carried out (MEDLINE 1966-97, CINAHL 1982-97) using the key words muscular dystrophy, rehabilitation, locomotion, braces or orthotic devices. References in relevant publications and nonindexed journals were also examined. Criteria to include and exclude articles were formulated. We used a systematic review procedure to evaluate the literature. Seven methodological criteria were formulated.

RESULTS

Thirty articles describing 35 studies met the inclusion criteria for our review, nine studies were selected based on completeness of information on study population, treatment and quantitative presentation of the effect outcome. Operations on the lower limbs were performed on most patients. A concomitant programme of rehabilitation was not described thoroughly. A percentage success of treatment was calculated for eight studies. Median percentage after one year was 75.1, after two years 47.9 and after three years 24.3. The median for the means of independent walking was 24 months, the median for the means of assisted walking was 36.2 months and the median for the means of standing ability was 50.5 months duration.

CONCLUSION

The scientific strength of the studies reviewed is poor. It seems that the use of knee-ankle foot orthoses can prolong assisted walking and standing, but it is uncertain whether it can prolong functional walking. The boys that benefit most have a relatively low rate of deterioration, are capable of enduring an operation and are well motivated.

Muscle and nerve biopsy in the evaluation of neuromuscular disorders: the surgeon's perspective

BACKGROUND/PURPOSE

A muscle biopsy frequently is requested by the neurologist evaluating a child with neuromuscular symptoms. However, there are no reports discussing the preoperative evaluation for, and diagnostic yield of, this procedure. The authors reviewed our experience over a 10-year period to obtain these data.

METHODS

The records of 153 patients who underwent muscle biopsy were reviewed with particular attention to the cardiology evaluation, the pathology report, and any resultant change in diagnosis and treatment of the child.

RESULTS

All 153 specimens contained adequate tissue for complete histological analysis. Preoperative cardiology consults were obtained in 82% of the children, with abnormalities found in 9%. Severe cardiac dysfunction was found in three children, all of whom had a previously diagnosed cardiomyopathy or dysrhythmia. No pathological abnormality was found in 41% of the muscle biopsy specimens, and nonspecific pathological findings were described in 23%. A specific diagnosis was made in 36%. Only 19% of the children had their treatment changed by the results of the muscle biopsy.

CONCLUSIONS

Muscle biopsies can be performed safely without routine preoperative cardiac evaluation. A specific diagnosis, however, may be made in less than half of the patients with a change in therapy available for even fewer.

Orthopedic management of neuromuscular disorders in children

In many cases, the orthopedic surgeon may be the first consultant requested to assess complaints of lower extremity weakness or deformity to result from such conditions and must remain alert to the primary diagnosis. In addition, the orthopedic surgeon should be prepared to guide appropriate physical therapy, prescribe orthotics, and perform surgery to improve function, prevent deformity, or provide comfort when necessary. Most deformities of the extremities result from a combination of muscle weakness and imbalance, and surgical procedures are aimed at correcting existing deformity and rebalancing existing musculature by release or transfer. Skeletally immature patients with neuromuscular disorders are also susceptible to the development of scoliosis, which may impair comfortable sitting or already compromised pulmonary function. This article reviews the clinical manifestation and orthopedic management of Duchenne's muscular dystrophy, spinal muscular atrophy, facioscapulohumeral dystrophy, and Charcot-Marie-Tooth disease.

In situ rigidity of a new sliding rod for management of the growing spine in Duchenne muscular dystrophy

STUDY DESIGN

This biomechanical, in vitro laboratory study determined the static stiffness of a new telescoping rod and the axial motion of this implant during various loading conditions.

OBJECTIVES

To compare the stability of the new telescoping rod with the classic Luque instrumentation, and to determine whether the sliding rod elongates or contracts during spine motion.

SUMMARY OF BACKGROUND DATA

A new telescoping rod was developed to stabilize the spine in children with Duchenne muscular dystrophy and to provide capacity for spinal growth.

METHODS

The stability of 11 instrumented calf spines was determined in flexion, extension, lateral bending, and torsion to determine the stiffnesses of the spines instrumented with these two implants. The telescoping motion in the left and right rod was measured in the new rod system.

RESULTS

In flexion, the spines with the telescoping rods were stiffer than those with the Luque implant. However, no significant differences in the stiffness coefficients were found for extension, lateral bending, or torsion. The restoring force of the telescoping system was greater than that of the Luque system in all directions. All modes of loading produced an accommodating change of length in the construct.

CONCLUSIONS

The dynamic telescoping system provides stiffness comparable with that of established systems while allowing elongation during growth of the young patient.

Spinal muscular atrophy type II (intermediary) and III (Kugelberg-Welander). Evolution of 50 patients with physiotherapy and hydrotherapy in a swimming pool

We added hydrotherapy to 50 patients with spinal muscular atrophy (SMA) who were being treated with individual conventional physiotherapy. Hydrotherapy performed at an approximate temperature of 30 degrees Celsius, twice a week, for thirty minutes in children and forty-five minutes in adults during a 2-year period. The outcome derived from this combined modality of treatment was rated according to physiotherapeutic evaluations, the MMT (Manual Muscular Test), and the Barthel Ladder. Patients were reevaluated at 2-month intervals. After two years of ongoing treatment, we were able to observe that the deformities in hip, knee and foot were progressive in all SMA Type II patients, and in some Type III. Muscle strength stabilized in most SMA Type III patients, and improved in some. MMT was not done in SMA Type II. In all patients we were able to detect an improvement in the Barthel Ladder scale. This study suggests that a measurable improvement in the quality of daily living may be obtained in patients with SMA Types II and III subjected to conventional physiotherapy when associated with hydrotherapy.

Spinal fusion in Duchenne's muscular dystrophy

The Women's and Children's Hospital experience with Luque spinal fusion in Duchenne's muscular dystrophy was reviewed from its commencement in 1983 to the present with a view to assessing the clinical and radiologic outcome and safety of the procedure. Seventeen boys have undergone spinal fusion. L-rod instrumentation was used in 10, six of whom had significant problems with sitting imbalance or progression of the scoliosis or both. In seven cases, distal instrumentation was taken to the pelvis with a Galveston construct and rigid crosslinking. Apart from some progression and sitting imbalance in the L-rod group, there were few complications. In the Galveston group, pelvic obliquity was corrected by a mean of 63%, and there was better maintenance of correction. There were no pseudoarthroses or instrument failures in the Galveston group. Of the total group, four patients had forced vital capacity (FVC) values < 25% predicted, and two required ventilation postoperative (< 48 h). There were no other respiratory complications. The effect of surgery on respiratory function remains uncertain. Spinal fusion with the Luque rod construct and pelvic fixation is a safe procedure. It provided a mean correction of 60% and control of pelvic obliquity without significant postoperative deterioration. In our experience, surgery can be safely performed with FVC value down to 20% predicted. On the basis of these data, one current practice is to instrument to the pelvis with a Galveston construct and Texas Scottish Rite Hospital cross-linking.

Effect of spinal surgery on lung function in Duchenne muscular dystrophy

BACKGROUND

The effect on subsequent respiratory function of spinal stabilisation for scoliosis in Duchenne muscular dystrophy is unclear. In order to clarify this clinical problem, changes in the forced vital capacity of a group of children with Duchenne muscular dystrophy who had undergone spinal surgery were measured and compared with a group of children with Duchenne muscular dystrophy who had not had surgery.

METHODS

In this retrospective study 17 boys with Duchenne muscular dystrophy who underwent spinal stabilisation at a mean age of 14.9 years (surgical group) were compared with 21 boys with Duchenne muscular dystrophy who had not had surgery (non-surgical group). The mean (SD) Cobb angle of the surgical group at 14.9 years was 57 (16.4) degrees, and of the non-surgical group at 15 years was 45 (29.9) degrees. Forced vital capacity expressed as percentage predicted (% FVC) was measured in total over a seven year period in the surgical group and over 6.5 years in the non-surgical group, and regression equations were calculated. Survival curves for both groups were also constructed.

RESULTS

No difference was found between spinal stabilisation (surgical group) and the non-surgical group in the rate of deterioration of % FVC which was 3-5% per year. There was no difference in survival in either group.

CONCLUSIONS

Spinal stabilisation in Duchenne muscular dystrophy does not alter the decline in pulmonary function, nor does it improve survival.