Cesarean section before the onset of labor and subsequent motor function in infants with meningomyelocele diagnosed antenatally

Background. Meningomyelocele can now be detected before birth. Few data are available on its natural history, however, and optimal management at the time of delivery is controversial, although it has been suggested that labor and vaginal delivery may cause pressure on exposed nerve roots, resulting in additional loss of neural function. Methods. To assess the effect of labor and the type of delivery on the level of motor function in fetuses with uncomplicated meningomyelocele, we identified 200 cases of this disorder, accounting for 95 percent of the cases that occurred in the state of Washington during our 10-year study period. We compared the outcomes of 47 infants delivered by cesarean section before labor began, 35 delivered by cesarean section after a period of labor, and 78 who were delivered vaginally (another 40 were ineligible for the study). In cases of meningomyelocele detected prenatally, cesarean section was performed before the onset of labor if isolated meningomyelocele without severe hydrocephalus was present. The infants delivered in this manner were compared with those who were delivered either vaginally or by cesarean section after labor began. Results. At two years of age, the infants who had been exposed to labor were 2.2 times more likely to have severe paralysis than those delivered by cesarean section without labor (95 percent confidence interval, 1.7 to 2.8). Infants delivered by cesarean section before the beginning of labor had a mean (+/- SD) level of paralysis 3.3 +/- 3.0 segments below the anatomical level of the spinal lesion at two years of age, as compared with 1.1 +/- 2.3 for infants delivered vaginally and 0.9 +/- 4.1 for infants delivered by cesarean section after the beginning of labor (P less than 0.001 for both comparisons). Exposure to labor did not affect the frequency of neonatal complications or later intellectual performance. Conclusions. For the fetus with uncomplicated meningomyelocele, delivery by cesarean section before the onset of labor may result in better subsequent motor function than vaginal delivery or delivery by cesarean section after a period of labor.

A new look at myelomeningoceles: functional level, vertebral level, shunting, and the implications for fetal intervention

OBJECTIVE

Previous reports have suggested that 80% to 85% of patients who have a myelomeningocele (MMC) and undergo surgical repair after birth develop hydrocephalus and require the placement of a ventricular shunt. However, the rate of shunting as a function of spinal level is not well established. We sought to determine the distribution of postnatally repaired MMC lesions as characterized by both functional and radiologic assessment, as well as the incidence of shunting when patients were categorized according to these 2 methods.

METHODS

A retrospective chart review of 297 patients who were born with open MMCs and followed in the spina bifida clinic at the Children's Hospital of Philadelphia was performed. The presence or absence of a shunt was determined for each patient. Functional spinal level was determined by the best-recorded neurologic examination and vertebral level by spine radiographs.

RESULTS

The overall rate of ventricular shunting was 81%. The level of the lesion significantly affected the incidence of shunting, with more cephalad lesions correlating with higher rates. This was true both for functional and radiologic categorizations. A significantly higher shunt rate was found among patients with sacral lesions when categorized by radiologic rather than functional criteria. In 86% of patients, the functional level was found to be equal to or higher (worse) than the radiologic level.

CONCLUSIONS

This study describes the natural history of ventricular shunting in MMC patients with relation to both radiologic and functional criteria. Fetal MMC closure is being performed in some centers in an attempt to decrease the incidence of shunting and to improve leg function in selected patients. The present data may serve as a comparison group and aid in the design and analysis of a prospective trial to assess the efficacy of this new procedure.

Endoscopic coverage of fetal myelomeningocele in utero

OBJECTIVE

Our goal was to evaluate the safety and efficacy of minimally invasive surgery for the coverage of myelomeningocele in utero.

STUDY DESIGN

Women in the mid-second trimester of a pregnancy complicated by fetal myelomeningocele were offered an experimental procedure designed to prevent ongoing exposure of the spinal cord to the intrauterine environment. The procedure consisted of maternal laparotomy while the patient was under both general and epidural anesthesia, with exposure of the gravid uterus. Endoscopic ports were placed for camera and operating instruments. Amniotic fluid was removed and replaced with carbon dioxide. The fetus was then positioned and a maternal split-thickness skin graft was placed over the exposed spinal cord or neural elements. The skin graft and a covering of Surgicel Absorbable Hemostat were attached with fibrin glue prepared from autologous cryoprecipitate.

RESULTS

Four fetuses with open myelomeningocele underwent endoscopic coverage of the spinal lesion between 22 weeks 3 days and 24 weeks 3 days of gestation. One infant, delivered by planned cesarean section at 35 weeks' gestation after demonstration of fetal lung maturity, is almost 3 years old. A second infant was delivered by cesarean section at 28 weeks after preterm labor and is now almost 6 months old. Both survivors manifest only mild motor and somatosensory deficits. One fetus who was delivered 1 week after operation after development of amnionitis died in the delivery room of extreme prematurity. The final fetus died intraoperatively from abruptio placentae.

CONCLUSION

Minimally invasive fetal surgery appears to constitute a feasible approach to nonlethal fetal malformations that result in progressive and disabling organ damage.

Clinical and radiographic predictors of scoliosis in patients with myelomeningocele

BACKGROUND

The prevalence of scoliosis in patients with myelomeningocele has been reported to be as high as 80% to 90% in some studies. However, those studies included patients with both congenital and developmental curves. The variation in the patient population as well as the definition of scoliosis in those studies made it difficult to predict the true prevalence of scoliosis in these patients. The purpose of the present study was to identify clinical and radiographic factors that may predict the onset of developmental scoliosis in patients with myelomeningocele.

METHODS

A retrospective review of the charts and radiographs of all patients with a diagnosis of myelomeningocele who were seen in our clinic between 1990 and 1995 was performed. The criteria for inclusion in the study included a diagnosis of myelomeningocele or lipomeningocele, an age of more than ten years at the time of the review, serial documentation of motor power, and radiographic documentation of spinal deformity primarily in the coronal plane. The radiographs were examined to assess the degree of scoliosis and to document the last intact laminar arch. The relationship between the degree of scoliosis and the last intact laminar arch was evaluated. Statistical analysis was performed to assess the association between scoliosis and the clinical motor level, the ambulatory status, spasticity, motor asymmetry, and hip instability.

RESULTS

One hundred and forty-one patients satisfied the criteria for inclusion in the study. Seventy-four patients (52%) had scoliosis. The average duration of follow-up was 9.4 years (range, three to thirty years), and the average age of the patients was nineteen years (range, ten to forty-two years). Scoliosis developed before the age of nine years in forty-three patients and after the age of nine years in thirty-one patients, with new curves continuing to develop until the age of fifteen years. Curves of <20 degrees degrees often resolved. The clinical motor level, ambulatory status, and last intact laminar arch were all found to be predictive factors for the development of scoliosis in these patients.

CONCLUSIONS

In the population of patients with myelomeningocele, the term scoliosis should be reserved for curves of >20 degrees. New curves may continue to develop until the age of fifteen years. The level of the last intact laminar arch is a useful early predictor of the development of scoliosis in these patients.

US of the spinal cord in newborns: spectrum of normal findings, variants, congenital anomalies, and acquired diseases

Ultrasonography (US) of the spinal cord is performed in newborns with signs of spinal disease (cutaneous lesions of the back, deformities of the spinal column, neurologic disturbances, suspected spinal cord injury due to traumatic birth, and syndromes with associated spinal cord compression). The examination is performed with high-frequency linear- and curved-array transducers in the sagittal and axial planes from the craniocervical junction to the sacrum. Normal variants such as transient dilatation of the central canal and ventriculus terminalis can be demonstrated with US. US allows detection of congenital malformations, such as myelocele or myelomeningocele, spinal lipoma, dorsal dermal sinus, tight filum terminale syndrome, diastematomyelia, terminal myelocystocele, lateral meningocele, caudal regression syndrome, and hydromyelia or syringomyelia. Acquired intraspinal diseases following birth trauma and transient alterations after lumbar puncture can also be detected with US. US can demonstrate the entire spectrum of intraspinal anatomy and pathologic conditions with high geometric resolution. Therefore, US should be considered the initial imaging modality of choice for investigating the spinal cord in newborns.

A new understanding of dorsal dysraphism with lipoma (lipomyeloschisis): radiologic evaluation and surgical correction

The spinal anomaly designated dorsal dysraphism with lipoma (lipomyeloschisis) consists of skin-covered, focal spina bifida; focal partial clefting of the dorsal half of the spinal cord; continuity of the dorsal cleft with the central canal of the cord above (and occasionally below) the cleft; deficiency of the dura underlying the spina bifida; deep extension of subcutaneous lipoma through the spina bifida and the dural deficiency to insert directly into the cleft on the dorsal half of the cord; variable cephalic extension of lipoma into the contiguous central canal of the cord; and variable ballooning of the subarachnoid space to form an associated meningocele. The variable individual expressions of the anomaly are best understood by reference to their archetypal concept. Careful analysis of radiographic and surgical findings in human lipomyeloschisis and correlation with an animal model of lipomyeloschisis indicate that plain spine radiographs and high-resolution metrizamide computed tomographic myelography successfully delineate the precise anatomic derangements associated with lipomyeloschisis and provide the proper basis for planning surgical therapy of this condition.

Myelomeningocele: prenatal evaluation--comparison between transabdominal US and MR imaging

PURPOSE

To compare transabdominal ultrasonography (US) with fetal magnetic resonance (MR) imaging in the prenatal evaluation of myelomeningocele lesion level.

MATERIALS AND METHODS

Prenatal US images, pre- and postnatal MR images, and postnatal spinal radiographs obtained in the first 100 fetuses who underwent intrauterine myelomeningocele repair were the basis for this study. Each image was used to assign a lesion level. The assigned levels were compared by means of the kappa statistic, as an index of agreement.

RESULTS

All fetuses underwent prenatal US. Sixty-one fetuses underwent prenatal MR imaging. Fifty fetuses underwent both postnatal spinal radiography and postnatal MR imaging, and an additional 34 fetuses underwent one postnatal study but not the other. When findings on prenatal US images were compared with those on postnatal radiographs, the findings agreed within one spinal level in 79% (55 of 70, kappa = 0.60) of cases. When findings on prenatal MR images were compared with those on postnatal radiographs, the findings agreed in 82% (31 of 38, kappa = 0.63) of cases. Findings on postnatal MR images and those on postnatal spinal radiographs agreed within one spinal level in 100% (50 of 50, kappa = 1.0) of cases.

CONCLUSION

Findings at prenatal MR imaging and prenatal US are equally accurate for the assignment of a lesion level in a fetus with myelomeningocele. Given that findings with both modalities will lead to misdiagnosis of the spinal level by two or more segments in at least 20% of cases, care should be exercised when neurologic outcome is predicted on the basis of these studies alone.

The nature of congenital posterior cervical or cervicothoracic midline cutaneous mass lesions. Report of eight cases

Between 4% and 8% of cases of spina bifida cystica occur in a cervical or cervicothoracic location. Despite a large body of literature concerning spinal dysraphism, there has been little written specifically about patients afflicted with this disorder in a cervical location. Eight children who presented at birth with posterior cervical or cervicothoracic lumps, all of which represented a dysraphic state, are discussed. Two types of abnormalities were noted. Three patients had hydromyelia with an associated myelocystocele herniating posteriorly into a meningocele sac. In these three patients there was an associated Chiari II malformation and hydrocephalus. The other five children had a meningocele in which a band of tissue extended from the posterior aspect of the spinal cord through a defect in the bone and fascia to the posterior part of the meningocele sac itself. No patient had a lesion that could be described as a meningomyelocele. The investigation and surgical management of these conditions are discussed and the need for intradural exploration to untether the spinal cord in the cervical region is stressed.

Surgical experience of 120 patients with lumbosacral lipomas

The surgical experience of 120 patients with lumbosacral lipomas is described. 47 of 120 patients were preoperatively found to be neurologically intact, the remaining 73 patients presented with various neurological signs including reflex changes, sensory disturbances, muscle weakness and sphincter problems. Neuro-imagings allowed a classification of lumbosacral lipomas into five types: (1) dorsal type; (2) caudal type; (3) combined type; (4) filar type; and (5) lipomyelomeningocele. Although all 120 patients underwent untethering of the spinal cord, the nerve roots passing through the lipoma itself and the neural tissues protruding externally to the spinal canal, respectively, tended to prevent satisfactory surgical removal of the lipoma in combined type lipomas and lipomyelomeningoceles. During 8.96 years of a mean postoperative follow-up period, there was no significant deterioration in most of the patients and some patients even improved in function. However, two patients with combined type lipomas developed neurological deterioration just after surgery, and five (two dorsal, two caudal and one combined type lipomas) did in the fashion of a late-onset. There are two different patient groups of lumbosacral lipomas; one group (caudal and filar type lipomas, and most of dorsal type lipomas) in whom the surgical anatomy is simple and satisfactory untethering surgery could be done without risk, and another (combined type lipomas and lipomyelomeningocele) in whom surgery would be accompanied with some risk and sometimes complete untethering could not be achieved because of the complicated anatomy of the lesion. Surgical difficulty of the latter group can be correlated with the increased frequency of neurological deterioration occurring just after the operation, but not of delayed one. Concerning prophylactic surgery for asymptomatic patients, the former group of patients are obviously good candidates, but the latter group is not.

Prevalence of ventriculomegaly in association with myelomeningocele: correlation with gestational age and severity of posterior fossa deformity

PURPOSE

To investigate the relationship of ventriculomegaly (VM) with gestational age (GA) and the severity of the associated Chiari II malformation.

MATERIALS AND METHODS

The sonograms of 51 fetuses with myelomeningoceles were retrospectively reviewed. VM was judged to be present when the transverse ventricular atrial diameter was greater than 10 mm. The severity of the posterior fossa (PF) deformity was subjectively graded as mild, moderate, or severe. Thirty-four fetuses were scanned at < or = 24 weeks GA, and 17 were scanned at > 24 weeks GA.

RESULTS

The prevalence of VM was 61%. However, only 44% of fetuses < or = 24 weeks GA had VM, whereas 94% of fetuses > 24 weeks GA had VM. When compared with fetuses with mild PF deformities, fetuses with moderate or severe deformities had a higher prevalence of VM and the largest ventricles.

CONCLUSION

The prevalence of VM in fetuses with myelomeningoceles varies with both GA and the severity of the associated PF deformity. These observations may provide additional prognostic information once a myelomeningocele is detected at sonography.

Prenatally detected myelomeningoceles: sonographic accuracy in estimation of the spinal level

The sonograms and case records of 53 patients with prenatally detected myelomeningoceles were retrospectively reviewed. Sonographic findings were correlated with pathologic, surgical, and/or radiographic findings in 28 cases. Fourteen mothers chose to continue their pregnancies, and the level of neuromotor deficit was available for 11 children of this group. The sonographic and pathologic levels were in agreement in 18 of 28 cases (64%) and were within one spinal level in 22 of 28 cases (79%). The pathologic level of the lesion was underestimated (sonographic level lower than pathologic) in three fetuses and overestimated (sonographic level higher than pathologic) in another three. In 10 of 11 living children (91%) the neuromotor level was equal to or better than the anatomic level. The authors conclude that ultrasonography can, in most cases, allow accurate prediction of the level of the spina bifida lesion and the severity of neuromotor handicap in children with prenatal diagnoses of myelomeningocele.

Prenatal spinal evaluation and functional outcome of patients born with myelomeningocele: information for improved prenatal counselling and outcome prediction

OBJECTIVE

Prenatal ultrasonography can localize the level of the spinal cord malformation, allowing prediction of the potential postnatal neurological deficit and functional prognosis.

METHODS

This study has two evaluations: (a) a retrospective prenatal review of 26 fetuses with spinal dysraphism (1987-1991), and (b) a follow-up descriptive study of patients (1971-1981) who underwent closure of the spinal lesion and ventricular shunting in the neonatal period.

RESULTS

Prenatal ultrasound evaluation enabled the accurate definition of the last intact vertebral level which allows separation of fetuses into three functional groups (last intact level L2, L3-4, L5-sacral). Patterns of ambulation, urinary and bowel continence, and school performance vary according to level of spinal lesion and the neurological deficit. The need for ventricular shunts, the incidence of other spinal malformations and surgical interventions did not vary with the level of the spinal lesion.

CONCLUSIONS

The functional outcome for patients with myelomeningocele is variable; however, distinct patterns emerge based on the level of spinal dysraphism and the resultant neurological deficit. By relating the level of the fetal spinal lesion to outcome data, more precise functional prognoses can be given to families.

Sonography of occult dysraphism in neonates and infants with MR imaging correlation

High-resolution spinal sonography has become an accepted study to screen for occult dysraphic lesions (ODLs) in neonates and infants. These defects are thought to be caused by abnormal fusion or closure of embryonic dorsal midline structures. Sonographic findings suggestive of an ODL include low position of the conus, nontapered bulbous appearance of the conus, dorsal location of the cord within the bony canal, solid or cystic masses in the distal canal or soft tissue of the back extending toward the canal, patulous distal thecal sac, and thick filum. Physical findings suggestive of ODLs include lumbosacral skin dimples, lumbosacral masses, lower extremity weakness, and an extra appendage arising from the back. The appearances of a normal infant spine, dorsal dermal sinus, lipoma, lipomyelomeningocele, lipomyelocele, myelocystocele, and diastematomyelia are depicted sonographically and correlate with those on magnetic resonance (MR) images. MR imaging is most useful when sonographic findings are abnormal or equivocal or when normal skeletal maturation limits sonographic visualization of the intracanalicular contents.

Tethered spinal cord following meningomyelocele repair

Of 16 consecutive patients with tethered spinal cord studied, most had undergone repair of a meningomyelocele. All were evaluated using somatosensory evoked potentials at 6 to 12-month intervals. Other possibilities include tethered filum terminale, lipomeningocele, membrana reuniens, and miscellaneous conditions (diastematomyelia, neurenteric cysts, etc.). Metrizamide myelography with polytomography was superior to gas myelography in showing a low-lying cord, obtuse nerve root angles, and a thin subarachnoid space between the cord and the dorsal meninges cephalad to the tether. Surgery is generally helpful in these patients.

Functional motor outcome in children with myelomeningocele: correlation with anatomic level on prenatal ultrasound

Fifteen children with prenatally diagnosed myelomeningocele were followed for at least three years to determine the relations between prenatal anatomic level visualized on high-resolution ultrasound, radiographic level, neuromotor level and functional motor outcome. Prenatal anatomic level accurately predicted neuromotor level and functional motor outcome in 12 of the children and was a better predictor than motor level at birth. Clinicians involved in prenatal counseling may use the anatomic level determined on high-resolution ultrasound to discuss motor prognosis with families.

Complications of myelomeningocele closure

Closure of a myelomeningocele is a deceptively simple operation; however, attention to several subtle details can significantly reduce operative complications. Important preoperative concerns include social issues of dealing with a distraught and often overwhelmed family, the timing of surgery, and assessment of associated severe or life-threatening malformations. Operative intervention should be directed toward preserving neurological function and optimizing the subsequent repair of a tethered spine should this become necessary. Careful attention to the vascular supply to the placode, precise separation of neural from cutaneous tissues, a diligent search for associated tethering anomalies such as diastematomyelia and a thickened filum terminale, careful pia to pia reconstruction of the placode, and simple but meticulous wound closure all help in achieving these aims. The timely management of associated hydrocephalus will help to avoid cerebrospinal fluid leakage and wound breakdown. Close attention to these details will ameliorate many of the immediate and delayed complications of myelomeningocele closure.

Initial urologic management of myelomeningocele

Disordered innervation of the detrusor musculature and external sphincter in patients with myelomeningocele adversely affects bladder function and potentially threatens the upper urinary tracts. Children with this condition can be categorized into high and low- risk groups for secondary damage from a neurogenic bladder based on intravesical pressure. Those with elevated pressure are at risk for hydronephrosis or reflux,and evidence suggests that early management of high pressure protects the bladder from additional damage, reducing the need for augmentation. Management decisions made during infancy potentially impact long-term outcomes for preserving renal function and achieving urinary continence. This discussion focuses on the initial urologic care of infants with myelomeningocele, emphasizing the controversy regarding urodynamic versus radiologic-based management of the neurogenic bladder.

Determinants of hydronephrosis and renal injury in patients with myelomeningocele

Renal injury is a major potential complication of patients with neurogenic bladder impairment. There are many clinical, radiological and urodynamic factors that are widely available and that may aid in predicting which patients are at risk of renal injury. This study aims at achieving an objective statistical analysis of these multiple risk factors. We have applied this statistical analysis in a prospective manner to 215 patients with myelodysplasia and neurogenic bladder impairment. Potential risk factors in the lower urinary tract include bladder capacity, contractility and dyssynergia. Each of these factors was assigned a numerical score of 0 to 3, which was correlated with the presence of vesicoureteral reflux. The upper urinary tracts in these patients were assigned a numerical score according to the degree of radiological changes observed. These results then were tested with a stepwise regression analysis using p equals 0.05 as the significance level. In this analysis significant determinants of vesicoureteral reflux included a change in bladder shape, the presence of uninhibited contractions and the presence of dyssynergia. Renal deterioration was noted, and it was predicted by the presence of vesicoureteral reflux, a high ureteral pressure profile and dyssynergia. We conclude from this clinical study that risk of renal injury is present in these children. We also conclude that the risk can be predicted by urodynamic and radiological criteria and that these data can be correlated and analyzed using statistical methodologies.

Change in spinal curvature following release of tethered spinal cord associated with spina bifida

Changes in spinal curvature, scoliosis, kyphosis and lordosis are associated with the growth of patients with myelomeningocele. Previous investigators have stated that progressive developmental scoliosis is related to tethered spinal cord. In order to investigate the relationship of tethered spinal cord release to progression of spinal curvature, we surveyed the medical records of 262 patients with a history of one or more tethered spinal cord release. For 216 of these patients, a total of 2,369 serial spine x-rays, obtained over a 20-year period, were reviewed by the standard Cobb method for progression of scoliosis, thoracic kyphosis and lordosis. In addition, the serial spine x-rays of 74 patients without clinical findings of tethered spinal cord were collected and reviewed for comparison of progressive scoliosis and kyphosis. One hundred and sixty normal lumbar x-rays were evaluated to compare the progression of the lordotic curve in patients with tethered cord release with a normal population. Progression of scoliosis plateaued or declined following release of tethered cord in patients with lumbar and sacral level lesions, however, tether release did not halt the progression of scoliosis in the thoracic level group. Tethered cord release altered the course of lordosis in L1 through L3 level lesions, but had little affect on the normal progression of lordosis in patients with L4, L5 or sacral level lesions. Finally, tethered spinal cord release appears to be associated with a decrease in the incidence and magnitude of kyphosis.

The role of intermittent catheterization in the management of children with myelomeningocele

Of 114 patients with myelomeningocele 44 (40 per cent) have no significant urologic disability. Intermittent catheterization has been used in 51 children and was helpful in 13 (26 per cent). Cystometrograms and urethral pressure profiles have been useful as predictive parameters. Causes of intermittent catheterization failures are discussed.

Prenatal ultrasound evaluation of segmental level of neurological lesion in fetuses with myelomeningocele: development of a new technique

OBJECTIVES

To report our preliminary experience in the use of prenatal ultrasound examination to assess lower-limb movements in fetuses with myelomeningocele. We aimed to determine the accuracy of this method to establish the segmental level of neurological lesion, as this is the best known predictor of the future ability to walk.

METHODS

This was a preliminary, observational study including fetuses with myelomeningocele operated on prenatally. The patterns of movements present and absent in the affected fetuses' lower limbs were evaluated systematically by ultrasound examination. According to the known nerve function associated with each muscle group, the segmental level of neurological lesion was established before birth. The agreement for the segmental levels assigned, between the prenatal ultrasound technique and the classical neurological clinical examination after birth (gold standard), was tested using the weighed kappa (wκ) index.

RESULTS

Seventy-one fetuses with myelomeningocele were evaluated at the Hospital Universitari Vall d'Hebron. After counseling, the parents opted for prenatal surgery (26 cases), termination of pregnancy (43 cases) or postnatal repair (two cases). Five patients did not fulfil the inclusion criteria for prenatal surgery and three were excluded after birth. In the 18 fetuses that underwent surgery and were analyzed, the agreement between prenatal and postnatal segmental levels assigned was 91.7% for the right limb (wκ = 0.80) and 88.9% for the left limb (wκ = 0.73).

CONCLUSIONS

The agreement found between prenatal and postnatal assignment of level of lesion in this preliminary study suggests that neurological sonographic evaluation is feasible before birth. This may provide accurate individualized information about the motor function and future ambulation prognosis of fetuses with myelomeningocele.

Children with spina bifida are at risk for low bone density

BACKGROUND

Patients with spina bifida frequently sustain lower extremity fractures which may be difficult to diagnose because they feel little or no pain, although the relative contributions of low bone density to pain insensitivity are unclear. Routine dual-energy xray absorptiometry (DXA) scanning is unreliable because these patients lack bony elements in the spine, and many have joint contractures and/or implanted hardware.

QUESTIONS/PURPOSES

We asked (1) if the lateral distal femoral scan is useful in spina bifida; (2) whether nonambulatory children with spina bifida exhibit differences in bone mineral density (BMD) compared with an age-and-sex-matched population; and (3) whether Z-scores were related to extremity fracture incidence.

METHODS

We retrospectively reviewed 37 patients with spina bifida who had DXA scans and sufficient data. Z-scores were correlated with functional level, ambulatory status, body mass index, and fracture history.

RESULTS

The distal femoral scan could be performed in subjects for whom total body and/or lumbar scans could not be performed accurately. Twenty-four of 37 had Z-scores below -2 SD, defined as "low bone density for age." Ten of 35 patients (29%) with fracture information had experienced one or more fractures. Our sample size was too small to correlate Z-score with fracture.

CONCLUSION

We believe BMD should be monitored in patients with spina bifida; nonambulatory patients with spina bifida and those with other risk factors are more likely to have low bone density for age than unaffected individuals. The LDF scan was useful in this population in whom lumbar and total body scans are often invalidated by contracture or artifact. Although lower extremity fractures occur regardless of ambulation or bone density, knowing an individual's bone health status may lead to interventions to improve bone health.

Current prognosis in fetal ventriculomegaly

A review of 51 cases referred for evaluation of fetal ventriculomegaly revealed adequate follow-up data in 40 patients. Three of the fetuses were electively aborted and 37 were delivered. There were no cases of death in utero. Of the 37 infants who were delivered, 26 (70%) were treated with shunt placement for neonatal hydrocephalus. The reasons for nontreatment included: inaccurate diagnosis, resolution of hydrocephalus by the time of delivery, neonatal death, and parental wishes. Survival time in the 26 shunt-treated patients ranged from 5 days to 14 years (average 4.25 years); five of these patients died within the first 2 weeks of life. Among the 26 treated patients, satisfactory cognitive ability was found in 10 (38%). Of the seven surviving nontreated infants, satisfactory cognitive ability was demonstrated in six (86%). Children with myelomeningocele displayed cognitive development similar to that in patients without myelomeningocele. The findings suggest that, of patients with in utero diagnosis of ventriculomegaly, approximately one-half survive (4-year average follow-up interval) and 38% of the survivors treated with shunt insertion have normal cognitive development. No subgroup likely to benefit from in utero treatment of ventriculomegaly was identified. Associated central nervous system or systemic malformations were identified in 26 (70%) of the 37 who came to delivery. This community-acquired series, not collected from a high-risk obstetrical-perinatal service, may reflect the general experience of the neurosurgeon consulting in such cases.

Posttraumatic pseudomeningomyelocele (enlarging fracture?) in a vertebral body. Case report

An unusual case is reported in which a posttraumatic peudomeningomyelocele developed over many years inside the body of a fractured lumbar vertebra, eroding the pedicle and causing progressive neurological deficit. The wall of the sac was mostly formed by the scalloped bar bone, and partly by a membrane resembling the dura. The terminal part of the conus medullaris and some nerve roots of the cauda equina formed the contents and parts of the wall of the outpouching of the subarachnoid space into the vertebral body. A comparison is drawn between this lesion and formation of an "enlarging fracture" of the skull. The surgical technique used for obliteration of this pseudomeningomyelocele is described.