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Mark S. Dias and Michael Partington

The authors review current views on of the embryogenesis of the neural tube defects (NTDs) myelomeningocele and anencephaly. In this context, the following four approaches to the study of NTDs are discussed: normal morphogenesis and timing of early human neural development from conception to the ascent of the conus medullaris; mechanical and molecular biology of neural tube closure derived from experimental and animal models; morphological and biomechanical features of the NTDs myelomeningocele and anencephaly; and the experimental evidence for the importance of both genetic and environmental influences on human NTDs. Although considerable insight into both normal neural tube closure and the factor(s) by which this process may be disrupted has been reported in recent years, the exact mechanism(s) by which human myelomeningoceles and anencephaly arise remain elusive.

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Michael D. Partington, Bernd W. Scheithauer and David G. Piepgras

✓ An elevated serum carcinoembryonic antigen (CEA) without evidence of neoplasia was noted in an 84-year-old woman. She subsequently developed a lytic skull lesion, which at surgery proved to be an atypical meningioma. Immunohistochemical analysis demonstrated that this tumor was producing CEA. This aggressive meningioma required two further resections and adjuvant radiotherapy in the following 18 months. Serum elevation of CEA has been reported only twice in association with meningiomas; both of those tumors were of the secretory subtype.

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Pituitary adenomas in childhood and adolescence

Results of transsphenoidal surgery

Michael D. Partington, Dudley H. Davis, Edward R. Laws Jr. and Bernd W. Scheithauer

✓ Pituitary adenomas are uncommon in childhood. Between 1975 and 1988, 36 patients underwent trans-sphenoidal resection at the Mayo Clinic before their 17th birthday. Fifteen (41.7%) had prolactin (PRL)-secreting tumors, 16 (44.4%) had adrenocorticotropic hormone (ACTH)-secreting tumors (including two patients with Nelson-Salassa syndrome), and three (8.3%) had tumors secreting growth hormone (GH); two patients (5.6%) had clinically nonfunctioning tumors. Of the 36 patients, 21 (58.3%) were girls, and girls predominated in every group except that with ACTH-secreting tumors, where they accounted for only 37.5% of the patients. The average age at the time of surgery was 14.7 ± 2.2 years, the youngest patient being 7.3 years old. The ACTH-secreting tumors were associated with an earlier onset of symptoms than the other tumor types: six (37.5%) of 16 patients became symptomatic before 10 years of age, compared with two (10.0%) of the 20 other patients. Presenting symptoms primarily reflected endocrine dysfunction, with neurological presentation (visual field deficits) occurring in only two patients.

There were no deaths in this patient group. Significant operative morbidity included steroid-induced psychosis in one patient and diabetes insipidus in three, which resolved in two. Plurihormonal tumors, broadly defined as tumors producing more than one hormone, were common, comprising five (36%) of 14 PRL-secreting tumors, all three GH-secreting tumors, and one of two clinically nonfunctioning tumors, or 25.7% overall. Macroadenomas accounted for 89% of plurihormonal tumors. Long-term follow-up review (median > 5 years) revealed good control of PRL-secreting tumors (although five of 15 patients had received postoperative radiotherapy), contrasted with a 25% late recurrence rate for ACTH-secreting tumors, which had an 80% initial remission rate. The majority of patients had good endocrine function, including reproductive function. It is concluded that: 1) although pediatric pituitary adenomas occur primarily in adolescence, Cushing's disease is found at any age; 2) transsphenoidal surgery is feasible and safe in this age group; 3) plurihormonal tumors occur more frequently in the pediatric age group than in adults; and 4) long-term control rates in PRL- and ACTH-secreting tumors are probably similar to those seen in adults.

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Emily Andrisevic, Marshall Taniguchi, Michael D. Partington, Julie Agel and Ann E. Van Heest

Object

The debate addressed in this article is that of surgical treatment methods for a neuroma-in-continuity. The authors of this study chose to test the hypothesis that more severe nerve injuries, as distinguished by < 50% conduction across a neuroma-in-continuity, could be treated with neuroma resection and grafting, whereas less severe nerve injuries, with > 50% conduction across the neuroma, could be treated with neurolysis alone.

Methods

The goal of this study was to compare preoperative and postoperative Active Movement Scale (AMS) scores in children with upper trunk brachial plexus birth injuries treated with neurolysis alone if the neuroma's conductivity was > 50% on intraoperative nerve testing. Seventeen patients (7 male, 10 female) met the criteria for inclusion in this study. Surgery was done when the patients were an average of 10 months old (range 6–19 months). The authors analyzed AMS scores from the preoperative assessment, 1-year postoperative follow-up visit, and subsequent follow-up assessment as close to 3 years after surgery as possible (referred to in this paper as > 2-year postoperative scores).

Results

Comparison of preoperative and 1-year follow-up data showed significant improvement in shoulder abduction, flexion, external rotation, and internal rotation; elbow flexion and supination; and wrist extension. Comparison of preoperative findings and results of assessment at > 2-year follow-up showed significant improvement in shoulder abduction, flexion, external rotation; and elbow flexion and supination. At final follow-up, useful function (AMS score of 6 or 7) was achieved for elbow flexion in 14 of 16 patients, shoulder flexion in 11 of 15 patients, shoulder abduction in 11 of 16 patients, and shoulder external rotation in 5 of 15 patients.

Conclusions

This report indicates that there is a subgroup of patients who can benefit clinically, with functional improvement of shoulder and elbow function, from treatment with neurolysis alone for upper trunk lesions demonstrating more than 50% conduction across the neuroma on intraoperative nerve testing. Patients with less than 50% conduction, indicating more severe disease, are treated with nerve resection and grafting in the authors' treatment algorithm.

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Michael D. Partington, Daniel A. Rüfenacht, W. Richard Marsh and David G. Piepgras

✓ The authors report a series of seven patients with myelopathy who were found to have spinal dural arteriovenous (AV) fistulas in which the nidus was located at some distance from the spinal cord. The nidus was intracranial in three cases and involved a sacral nerve root sheath in the other four, in each case, the arterialized draining vein led into the coronal plexus of medullary veins. A lack of normal draining radicular veins was noted in all cases. Magnetic resonance images were obtained in four patients and demonstrated spinal cord tissue changes only in the lower thoracic cord in three cases and in the cervical cord in one, all consistent with an ischemic process secondary to venous hypertension. Five patients were managed surgically by division of the draining vein, with improvement of the neurological deficit in all. One patient was treated by embolization alone and had stabilization of her deficit. The remaining patient in the series died of unrelated systemic disease before the spinal dural AV fistula could be treated.

These cases support the theory that venous hypertension is the dominant pathophysiological mechanism involved in spinal dural AV fistulas independent of their location. In patients with a suspected spinal dural AV fistula, lumbar and thoracic spinal angiography will reveal the site of the fistula in the majority of cases (88% in this series). In the remaining patients, the possibility of a remote fistula must be considered. The lack of normal venous drainage of the cord following injection in the artery of Adamkiewicz is the most reliable indicator of venous hypertension in the cord and can be helpful in making the decision to proceed with a search for a cranial or sacral arterial supply.

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Willem Pondaag and Martijn J. A. Malessy

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Irene Kim, Betsy Hopson, Inmaculada Aban, Elias B. Rizk, Mark S. Dias, Robin Bowman, Laurie L. Ackerman, Michael D. Partington, Heidi Castillo, Jonathan Castillo, Paula R. Peterson, Jeffrey P. Blount and Brandon G. Rocque

OBJECTIVE

The purpose of this study was to determine the rate of decompression for Chiari malformation type II in individuals with myelomeningocele in the National Spina Bifida Patient Registry (NSBPR). In addition, the authors explored the variation in rates of Chiari II decompression across NSBPR institutions, examined the relationship between Chiari II decompression and functional lesion level of the myelomeningocele, age, and need for tracheostomy, and they evaluated for temporal trends in rates of Chiari II decompression.

METHODS

The authors queried the NSBPR to identify all individuals with myelomeningocele between 2009 and 2015. Among these patients, they identified individuals who had undergone at least 1 Chiari II decompression as well as those who had undergone tracheostomy. For each participating NSBPR institution, the authors calculated the proportion of patients enrolled at that site who underwent Chiari II decompression. Logistic regression was performed to analyze the relationship between Chiari II decompression, functional lesion level, age at decompression, and history of tracheostomy.

RESULTS

Of 4448 individuals with myelomeningocele identified from 26 institutions, 407 (9.15%) had undergone at least 1 Chiari II decompression. Fifty-one patients had undergone tracheostomy. Logistic regression demonstrated a statistically significant relationship between Chiari II decompression and functional lesion level of the myelomeningocele, with a more rostral lesion level associated with a higher likelihood of posterior fossa decompression. Similarly, children born before 2005 and those with history of tracheostomy had a significantly higher likelihood of Chiari II decompression. There was no association between functional lesion level and need for tracheostomy. However, among those children who underwent Chiari II decompression, the likelihood of also undergoing tracheostomy increased significantly with younger age at decompression.

CONCLUSIONS

The rate of Chiari II decompression in patients with myelomeningocele in the NSBPR is consistent with that in previously published literature. There is a significant relationship between Chiari II decompression and functional lesion level of the myelomeningocele, which has not previously been reported. Younger children who undergo Chiari II decompression are more likely to have undergone tracheostomy. There appears to be a shift away from Chiari II decompression, as children born before 2005 were more likely to undergo Chiari II decompression than those born in 2005 or later.

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Irene Kim, Betsy Hopson, Inmaculada Aban, Elias B. Rizk, Mark S. Dias, Robin Bowman, Laurie L. Ackerman, Michael D. Partington, Heidi Castillo, Jonathan Castillo, Paula R. Peterson, Jeffrey P. Blount and Brandon G. Rocque

OBJECTIVE

Although the majority of patients with myelomeningocele have hydrocephalus, reported rates of hydrocephalus treatment vary widely. The purpose of this study was to determine the rate of surgical treatment for hydrocephalus in patients with myelomeningocele in the National Spina Bifida Patient Registry (NSBPR). In addition, the authors explored the variation in shunting rates across NSBPR institutions, examined the relationship between hydrocephalus, and the functional lesion level of the myelomeningocele, and evaluated for temporal trends in rates of treated hydrocephalus.

METHODS

The authors queried the NSBPR to identify all patients with myelomeningoceles. Individuals were identified as having been treated for hydrocephalus if they had undergone at least 1 hydrocephalus-related operation. For each participating NSBPR institution, the authors calculated the proportion of patients with treated hydrocephalus who were enrolled at that site. Logistic regression was performed to analyze the relationship between hydrocephalus and the functional lesion level of the myelomeningocele and to compare the rate of treated hydrocephalus in children born before 2005 with those born in 2005 or later.

RESULTS

A total of 4448 patients with myelomeningocele were identified from 26 institutions, of whom 3558 patients (79.99%) had undergone at least 1 hydrocephalus-related operation. The rate of treated hydrocephalus ranged from 72% to 96% among institutions enrolling more than 10 patients. This difference in treatment rates between centers was statistically significant (p < 0.001). Insufficient data were available in the NSBPR to analyze reasons for the different rates of hydrocephalus treatment between sites. Multivariate logistic regression demonstrated that more rostral functional lesion levels were associated with higher rates of treated hydrocephalus (p < 0.001) but demonstrated no significant difference in hydrocephalus treatment rates between children born before versus after 2005.

CONCLUSIONS

The rate of hydrocephalus treatment in patients with myelomeningocele in the NSBPR is 79.99%, which is consistent with the rates in previously published literature. The authors’ data demonstrate a clear association between functional lesion level of the myelomeningocele and the need for hydrocephalus treatment.