Neuromuscular Scoliosis Treatment & Management

The 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.^[3]

The 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.^[4]

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.^{[5, 6, 7, 8, 9]} 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.^{[10, 11, 12, 13, 14, 15, 16]}

To 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.^[17]

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.^[18]

Patients with Duchenne muscular dystrophy and Friedreich ataxia should be evaluated for cardiac involvement.^[19]

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.^{[20, 21]}

Intraoperative 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 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.^[22]

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.

The postoperative images below depict the same patient shown preoperatively above.

Hospital 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.

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.

• Respiratory problems: A child with neuromuscular disease often has some degree of intercostal paralysis and a poor cough reflex. As a result, the incidence of postoperative pneumonia is high. To minimize this problem, attention to postoperative respiratory care is essential. It is common to leave the endotracheal tube in place 1 or 2 days after the operation.
• Ileus: Intestinal hypomotility may persist, necessitating prolonged parenteral support.
• Nutritional problems: When intestinal motility returns postoperatively but the child cannot tolerate oral feedings, a feeding tube can be passed into the stomach or duodenum to allow nutritional support until oral feeding is tolerated.
• Hip problems: Hip subluxation, dislocation, and contracture are frequent among patients who do not walk. Parents and caregivers should be told that the hip position might appear worse after the operation when contractures are present preoperatively. Gentle hip range of motion can be started postoperatively, but no stretching is allowed. These restrictions are in effect until the fusion is solid to avoid putting the sacral fixation in jeopardy.
• Crankshaft phenomenon: Continued anterior spinal growth in the presence of a solid posterior fusion can occur in these children because many of them undergo fusion at a young age. Crankshaft phenomenon can be prevented with anterior fusion. However, the prospect of adding an anterior approach to an operation on a patient with respiratory compromise must be considered.

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.

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.^[23]

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.^[24]

The intraoperative use of halo-femoral traction aids in the correction of pelvic obliquity and is becoming more widely used.^[25]