You are in: eMedicine Specialties > Orthopedic Surgery > SPINE Neuromuscular ScoliosisArticle Last Updated: Apr 24, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Matthew B Dobbs, MD, Associate Professor of Orthopedic Surgery and Chief of Pediatric Orthopa, Associate Professor of Orthopaedic Surgery, Department of Orthopaedic Surgery, Washington University School of Medicine Matthew B Dobbs is a member of the following medical societies: Alpha Omega Alpha, American Academy of Orthopaedic Surgeons, and American Medical Association Coauthor(s): Lawrence G Lenke, MD, Jerome J Gilden Professor of Orthopedic Surgery, Section of Spinal Surgery, Director of Residency Program, Washington University School of Medicine; Chief of Spinal Surgery, Department of Orthopedic Surgery, St Louis Shriners Hospital Editors: Lee H Riley III, MD, Chief, Division of Orthopedic Spine Surgery, Assistant Professor, Departments of Orthopedic Surgery and Neurosurgery, Johns Hopkins University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; William O Shaffer, BS, MD, Professor, Vice-Chairman and Residency Program Director, Department of Orthopedic Surgery, University of Kentucky at Lexington; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Mary Ann E Keenan, MD, Professor, Vice Chair for Graduate Medical Education, Department of Orthopedic Surgery, University of Pennsylvania School of Medicine; Chief of Neuro-Orthopedics Program, Department of Orthopedic Surgery, Hospital of the University of Pennsylvania Author and Editor Disclosure Synonyms and related keywords: cerebral palsy, muscular dystrophy, spinal deformity, neuromuscular disease, Duchenne muscular dystrophy, myelodysplasia, syringomyelia, spinal cord trauma, poliomyelitis, spinal muscular atrophy, arthrogryposis INTRODUCTIONSection 2 of 12
  Scoliosis is a common deformity in many types of neuromuscular diseases. It is generally most severe in nonambulatory patients. Severe curves of the vertebral column cause difficulties in sitting. Bracing neuromuscular curves does not affect the natural history of scoliosis and is not definitive treatment. Progressive curves require surgical correction and stabilization. For excellent patient education resources, visit eMedicine's Bone Health Center and Back, Ribs, Neck, and Head Center. Also, see eMedicine's patient education article Scoliosis. History of the ProcedureSurgical stabilization constitutes the mainstay of treatment for neuromuscular scoliosis. ProblemNeuromuscular scoliosis can be defined as a coronal and sagittal plane deformity of the spine in patients with abnormalities of the myoneural pathways of the body. In neuromuscular spinal deformities, progression occurs much more frequently than in idiopathic scoliosis. In addition, progression often continues into adulthood. The long-term effects of the spinal deformity in patients with neuromuscular conditions can be disabling. Loss of the ability to sit occurs, as does an accompanying decrease in overall function. In addition, pulmonary function is markedly affected. FrequencyBecause neuromuscular scoliosis has so many causes, the patterns and incidence vary greatly. However, the prevalence of spinal deformity in the patient with a neuromuscular disorder is much higher than in the general population. It ranges from 20% in children with cerebral palsy to 60% in patients with myelodysplasia. The prevalence rises to 90% in males with Duchenne muscular dystrophy. In general, the greater the neuromuscular involvement, the greater the likelihood and severity of scoliosis. EtiologyScoliosis associated with neuromuscular disorders has been classified by the Scoliosis Research Society into neuropathic and myopathic types. The neuropathic conditions have been subdivided into those with upper and lower motor neuron lesions. The group with upper motor neuron lesions includes diseases such as cerebral palsy, syringomyelia, and spinal cord trauma; the group with lower motor neuron lesions includes poliomyelitis and spinal muscular atrophy. The myopathic conditions include arthrogryposis, muscular dystrophy, and other forms of myopathy. PathophysiologyThe pathophysiology is not well understood. It seems logical to assume that scoliosis in these conditions is caused by muscle weakness, but this conclusion is difficult to support because some conditions are accompanied by spasticity and others by flaccidity. Furthermore, no consistent pattern of scoliosis is associated with a particular pattern of weakness. ClinicalThe evaluation of a patient with neuromuscular scoliosis entails a thorough assessment of all body systems. Accurate diagnosis of the underlying disease entity is essential and may require muscle biopsy. Assessing nutritional status and pulmonary function is extremely important. The child's caregivers should be interviewed to gain an appreciation of the patient's functional level. The orthopedic examination includes assessment of all extremities and joints for contractures. Spinal deformity, decompensation, and shoulder balance are documented. Ambulatory status is also evaluated, and patients are classified as walkers, sitters, or nonsitters. INDICATIONSSection 3 of 12
The 2 main indications for surgery are curve progression and deterioration in sitting ability. RELEVANT ANATOMYSection 4 of 12
Understanding the anatomy of the spine is crucial for safe and efficient exposure with a posterior approach. The incision is made from the spinous process above the most proximal vertebra to be instrumented to the most caudal extent of the proposed instrumented area. Identifying and staying in the midline is important so that muscle is not cut, which would lead to bleeding. The midline is identified by a thin line, which is actually the interspinous ligaments connecting the spinous processes. Each vertebral level is exposed in a similar manner. An elevator is used to pull the soft tissue off of the spinous process, lamina, and transverse process of each respective level. To minimize blood loss, expose each segment completely the first time; do not leave soft tissue on the bone that will have to be removed later. CONTRAINDICATIONSSection 5 of 12
A preoperative assessment of respiratory competency, cardiac status, nutrition, possible feeding difficulties, seizure disorders, urologic status, and metabolic bone disease is necessary to ensure that the patient is healthy enough to tolerate surgery. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
Other Tests
TREATMENTSection 7 of 12
Medical therapyThe goal of nonoperative and operative treatment of patients with neuromuscular scoliosis is the same: to maintain the spine in a balanced position in the coronal and sagittal planes over a level pelvis. This goal is achieved with a custom molded thoracolumbosacral orthosis (TLSO) and molded seating supports. The aim is to control the curve during spinal growth rather than to correct the spinal deformity. Controlling the curve during spinal growth may delay the need for surgical stabilization and is possible for most patients in the juvenile years. With the onset of the pubertal growth spurt, however, control of the curve is often lost, and surgical stabilization becomes necessary.1 Surgical therapyThe surgical principles in the management of neuromuscular scoliosis differ from those in idiopathic scoliosis. Fusion is necessary at a younger age, and the fused portion of the spine is longer. Fusion to the sacrum is fairly common because many of these children do not have sitting balance or have pelvic obliquity. Combined anterior and posterior fusion is common in the treatment of patients with neuromuscular scoliosis, either because posterior elements are absent, as in myelodysplasia, or because it is necessary to gain correction in a rigid lumbar or thoracolumbar curve and achieve a spine fused in balance over a level pelvis.2, 3, 4, 5, 6 The instrumentation used is segmental, with either a multiple hook-rod system, with or without the addition of sublaminar wires, or a Luque rod and sublaminar wires or a unit rod device. When fusion to the sacrum is necessary, it can be performed with the Luque-Galveston technique or with iliac screws.7, 8, 9, 10, 11 Preoperative detailsTo ensure that the patient can tolerate reconstructive spinal surgery, a detailed preoperative history and assessment should include an evaluation of respiratory competency, cardiac status, nutrition, possible feeding difficulties, seizure disorders, urologic status, and metabolic bone disease.12 Patients capable of cooperating should be evaluated with pulmonary function studies. Patients with vital capacities less than 30% of the predicted reference value may require postoperative ventilatory support. Performing formal pulmonary function testing is difficult in patients with neuromuscular scoliosis because patients are often unable to cooperate.13 Patients with Duchenne muscular dystrophy and Friedreich ataxia should be evaluated for cardiac involvement.14 Poor nutritional status is strongly linked to perioperative complications in these patients. Nutritional deficiencies should be corrected preoperatively through a forced nutritional improvement schedule or postoperatively with feeding tubes. Elective placement of gastric feeding tubes 3 months preoperatively dramatically improves nutritional status. The use of total parenteral nutrition (TPN) perioperatively also can be helpful in decreasing problems with wound infections.15, 16 Intraoperative detailsIntraoperative replacement of blood can be decreased with the use of a cell-saving device. The judicious use of blood products, including fresh frozen plasma and platelet and clotting factor replacements, can prevent disseminated intravascular coagulation. Because inadequate iliac autograft is available in many of these operations, either because the iliac crest is small or because iliac fixation is used, graft augmentation with allograft or a bone graft substitute is required. Malignant hyperthermia, characterized by muscular rigidity and increased body temperature, occurs with some frequency in certain neuromuscular disorders and is triggered by inhalational anesthetics and succinyl choline. This should be a consideration in all patients with neuromuscular conditions who are undergoing general anesthesia. Postoperative detailsPostoperative care for these patients is demanding. Attention must be paid to pulmonary support, fluid status, and nutrition in addition to the elements of routine postoperative monitoring. 17 Patients should be mobilized as rapidly as possible for a return to preoperative ambulatory and functional status. Because of the secure fixation obtained with segmental fixation systems and the lower functional demands of these patients, postoperative immobilization is rarely needed (see Image 4, Image 5, Image 6). Follow-upHospital stays are usually 7-10 days. Modifications in the child's wheelchair should be made as soon as possible to accommodate the new sitting position. The number of hours spent upright each day should be gradually increased. The wound should be assessed 3 weeks postoperatively. Radiographs should be obtained 6 weeks postoperatively and again 3 and 6 months after surgery. COMPLICATIONSSection 8 of 12
Because of the multitude of medical comorbidities of these patients, the complication rate after surgery is high. Some complications, however, are more common or significant than others and are included in this discussion. These include respiratory problems, ileus, nutritional problems, hip problems, and crankshaft phenomenon.
OUTCOME AND PROGNOSISSection 9 of 12
With care in surgical technique and adequate postoperative care, complications can be minimized. The patient can return to the preoperative functional level with a successful surgical result, which consists of a solidly fused spine in balance in the coronal and sagittal planes over a level pelvis. FUTURE AND CONTROVERSIESSection 10 of 12
In patients requiring combined anterior and posterior spinal fusion, the issue of whether to perform these fusions as staged or same-day surgery remains unsettled. Combined anterior-posterior procedures facilitate spinal correction and a higher union rate in the neuromuscular population. The question of morbidity associated with same-day versus that associated with staged procedures has not been fully resolved. 18 Intraoperative monitoring has become a standard of care for spinal deformity surgeries. The combination of somatosensory and motor evoked potentials is widely accepted to be accurate and effective in detecting neurologic deficit in most patients during spine surgery. However, the success of this form of monitoring in the patient with neuromuscular scoliosis is still a matter of debate.19 The intraoperative use of halo-femoral traction aids in the correction of pelvic obliquity and is becoming more widely used.20 MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Neuromuscular Scoliosis excerpt Article Last Updated: Apr 24, 2008 | ||||||||||||||||||||||||||||||||||||||||||
