Sagittal static imbalance in myelomeningocele patients: improvement in sitting ability by partial and total gibbus resection

Abstract

IntroductionThe myelomeningocele (MMC) is one of the dysraphic disorders of the neural arch. Pathogenically it is caused by the absence of proliferation of neuroectodermal cells after migration is finished. The occult form without neurologic deficit is estimated to have incidence of up to 1%, while a spina bifida aperta cystica with everted myelon and complete paraplegia occurs in 0.005% of live births. With the help of postnatal closure of the sac and the early commencement of hydrocephalus therapy, the life expectancy of patients with myelomeningocele has nearly reached the level of the normal population [3,24]. While therapy during infancy concentrates on taking care of the cerebral and renal function, during growth and adolescence, more and more problems concerning the skeletal system arise, caused by the wish for maximum mobility and improved nursing aspects such as lying in supine position and sitting without support. The clinical appearance is dominated by the spastic or paralytic neurological lesion at different levels. In addition, the increasing spinal deformity in combination with trophic skin and soft tissue disturbances leads to secondary problems, i.e. decubital ulcers and contractures of hips and limbs. Kyphosis appears in 12-28% of the cases, with neurologic damage at the thoracic level [2,15,24, 25]. The gibbus, however, develops usually between L2 and L5 [4]. Problems of the kyphotic spineMyelomeningocele at the thoracic level is in most cases accompanied by other malformations of the neural arch. They can aggravate each other, if for example during progressive kyphosis the dura is pulled caudally by a tethered Abstract The progression of kyphosis in myelomeningocele is independent of skeletal growth and requires early operative correction and stabilization to prevent a loss of sitting ability. In severe cases, only vertebrectomy makes it possible to achieve correction, stability and skin-closure without tension. In 14 patients with myelomeningocele gibbus, kyphectomy was performed, removing two vertebral bodies on average. The average kyphosis angle decreased from 128°to 81°, enabling most of the patients to participate again in social life by restoring wheelchair mobility. Nevertheless, a significantly higher complication rate was found compared to other correctional operations, lengthening the average hospital stay to 41 days. Special problems arose from trophic disorders of the skin and soft tissue and from the dystrophic muscles below the level of neural malfunction. In three cases, kyphosis reappeared cranial to the fused segments, requiring ventral stabilization. With respect to increasing kyphosis angle, an early intervention should be aimed at. A secondary operation can be necessary, if surgery is performed without taking care of the growth potential.

Posterior Kyphectomy for Myelomeningocele With Anterior Placement of Fixation: A Retrospective Review

“…This is especially important in the MMC population in which patients frequently have comorbid illnesses. The only exception to our lower operative time was Furderer's study of 14 patients in which his operative time was 216 minutes; however, his blood loss was 1194 mL as compared with the mean of 765 mL in our study [6] . Estimated blood loss in other series of patients ranged from 155 mL to 3000 mL (Table 3).…”

“…Estimated blood loss in other series of patients ranged from 155 mL to 3000 mL (Table 3). Despite a couple of outliers [4,30], the remainder of studies reported blood loss greater than 800 mL [6,20,22,27,28,32]. Longer operative times and the extent of distal exposure in their techniques likely resulted in greater blood loss.…”

“…Although techniques for treatment of this condition have evolved, a definitive ''gold standard'' procedure, with uniformly predictable outcomes, remains elusive. The incidence of MMC is between 0.005% and 0.2% of all live births [6,7]. Deformities in MMC occur in 50% of patients [7].…”

“…Deformities in MMC occur in 50% of patients [7]. Congenital kyphosis and kyphoscoliosis are less common than congenital scoliosis [24,25], occurring in 8% to 28% of these patients [4,6,12,18,22,26,28,34].…”

“…Nonoperative treatment in the form of bracing, manual reduction, or observation to allow deformities to stabilize or the patient to reach skeletal maturity is often not successful [3,4,8,12,16,17,26,28]. Other indications include sagittal imbalance (such that the patient needs to use the upper extremities for sitting) [3,5,6,14,16,17,[26][27][28][29]31] and progressive deformity [6,10,11,13,21,31,34].…”