Tethered cord release in patients after open fetal myelomeningocele closure: intraoperative neuromonitoring data and patient outcomes.

PURPOSE: The purpose of the study was to better understand the clinical course and impact of tethered cord release surgery on patients who have previously undergone open spinal dysraphism closure in utero. METHODS: This is a single-center retrospective observational study on patients undergoing tethered cord release after having previously had open fetal myelomeningocele (MMC) closure. All patients underwent tethered cord release surgery with a single neurosurgeon. A detailed analysis of the patients' preoperative presentation, intraoperative neuromonitoring (IONM) data, and postoperative course was performed. RESULTS: From 2009 to 2021, 51 patients who had previously undergone fetal MMC closure had tethered cord release surgery performed. On both preoperative and postoperative manual motor testing, patients were found to have on average 2 levels better than would be expected from the determined anatomic level from fetal imaging. The electrophysiologic functional level was found on average to be 2.5 levels better than the anatomical fetal level. Postoperative motor levels when tested on average at 4 months were largely unchanged when compared to preoperative levels. Unlike the motor signals, 46 (90%) of patients had unreliable or undetectable lower extremity somatosensory evoked potentials (SSEPs) prior to the tethered cord release. CONCLUSION: Tethered cord surgery can be safely performed in patients after open fetal MMC closure without clinical decline in manual motor testing. Patients often have functional nerve roots below the anatomic level. Sensory function appears to be more severely affected in patients leading to a consistent motor-sensory imbalance.

Neonatal intraoperative neuromonitoring in thoracic myelocystocele: a case report.

Thoracic myelocystocele are extremely rare, non-terminal, closed neural tube defects. Intraoperative neuromonitoring (IONM) is a mainstay of pediatric spinal surgery. However, in neonates and infants, incomplete myelination of the corticospinal tract presents unique challenges to successful use of IONM in this vulnerable patient population. Surgery can often be delayed until patients are older, but there are circumstances in which early intervention is necessary. We report a case of T6 myelocystocele resection and wound closure in an infant on day of life 15 with the use of IONM. To our knowledge, this is the youngest reported patient to undergo successful IONM in the spinal cord. Given that the majority of thoracic myelocystoceles present without any neurological deficits, early intervention for this rare closed spinal dysraphism is sometimes necessary. This case study reports the possibility of IONM use in neonatal patients and also highlights the techniques that make its use more possible.

Safe transcranial electric stimulation motor evoked potential monitoring during posterior spinal fusion in two patients with cochlear implants.

Transcranial electric stimulation (TES) motor evoked potentials (MEPs) have become a regular part of intraoperative neurophysiologic monitoring (IONM) for posterior spinal fusion (PSF) surgery. Almost all of the relative contraindications to TES have come and gone. One exception is in the case of patients with a cochlear implant (CI). Herein we illustrate two cases of pediatric patients with CIs who underwent PSF using TES MEPs as part of IONM. In both instances the patients displayed no untoward effects from TES, and post-operatively both CIs were intact and functioning as they were prior to surgery.

Transcranial electric motor evoked potential monitoring during scoliosis surgery in children with cerebral palsy and active seizure disorder: is it feasible and safe?

PURPOSE: Use of spinal cord monitoring in children with cerebral palsy (CP) and neuromuscular scoliosis is challenging. The previous reports suggest low success rates in the setting of CP, and it is unclear if transcranial electric motor evoked potentials (TcMEP) monitoring is contraindicated in patients with an active seizure disorder. The purpose of this study was to determine (1) are patients with CP able to be appropriately monitored with TcMEP? and (2) does TcMEP cause an increase in seizure activity? METHODS: This was an institutional review board-approved retrospective cohort study observing 304 patients from 2011 to 2020. Inclusion criteria included all patients with CP undergoing posterior spinal fusion during this time. Intraoperative data were examined for the ability to obtain monitoring and any intraoperative events. Patients were followed for 3 months postoperatively to determine any increase in seizure activity that could have been attributed to the TcMEP monitoring. RESULTS: Of the 304 patients who were observed, 21% (20.8%) were unable to be monitored due to lacking baseline signals from the extremities. Seventy-seven percent (77.5%) were successfully monitored with TcMEP. For these patients, no increased seizure activity was documented either intra- or postoperatively. CONCLUSION: A high percentage of children (77.5%) with CP were able to be successfully monitored with TcMEP during posterior spinal fusion. Furthermore, the concerns about increased seizure activity after TcMEP were not supported by the data from this cohort. Technical details of successful neuromonitoring in these patients are important and included increased stimulation voltage requirements and latency times. LEVEL OF EVIDENCE: III retrospective comparative study.

Prophylactic Decompression for Cervical Stenosis in Jeune Syndrome: Report From a Single Institution.

STUDY DESIGN: This is a level IV retrospective descriptive study at a single institution. OBJECTIVE: The objective of the study was to determine the preoperative signs or symptoms prompting cervicomedullary imaging in Jeune syndrome. SUMMARY OF BACKGROUND DATA: Jeune syndrome is a rare autosomal recessive disorder that results in pulmonary compromise from abnormal development of the thorax. Multiple medical comorbidities complicate timely diagnosis of cervicomedullary stenosis, which neurologically jeopardizes this patient population with regards to improper cervical manipulation. Currently, explicit screening of the cervicomedullary junction is not advocated in national guidelines. METHODS: The User Reporting Workbench and Center for Thoracic Insufficiency Syndrome (CTIS) Safety Registry was queried for patients with Jeune syndrome under the age of 18 with cervicomedullary stenosis with or without suboccipital craniectomy/craniotomy evaluated at the authors' institution from January 1, 2007 to August 21, 2018. The primary outcome was the clinical reason for cervicomedullary screening. Secondary outcomes were: age at time of surgery, preoperative myelopathy (spasticity, urinary retention), hydrocephalus, postoperative deficits (respiratory, motor, swallowing difficulty), and need for cervical fusion. RESULTS: Of 32 patients with Jeune syndrome, four (12.5%) had cervicomedullary stenosis requiring decompression. The average age at surgery was 5.25 months (2-9 mo). Two patients underwent imaging due to desaturation events while the other two patients were diagnosed with cervical stenosis as an incidental finding. No patients exhibited clinical myelopathy. Two patients had baseline preoperative swallowing difficulties. None of the patients postoperatively required cervical fusions, nor did they exhibit respiratory deficits, motor deficits, or worsening swallowing difficulties. CONCLUSION: Jeune patients should be routinely screened for cervicomedullary stenosis and undergo subsequent prophylactic decompression to minimize or eliminate the development of irreversible neurologic compromise. LEVEL OF EVIDENCE: 4.

Sensitization of the Hypothalamic-Pituitary-Adrenal Axis in a Male Rat Chronic Stress Model.

Stress activation of the hypothalamic-pituitary-adrenal (HPA) axis is regulated by rapid glucocorticoid negative feedback. Chronic unpredictable stress animal models recapitulate certain aspects of major depression in humans, which have been attributed to impaired glucocorticoid negative feedback. We tested for an attenuated HPA sensitivity to fast glucocorticoid feedback inhibition in male rats exposed to a chronic variable stress (CVS) paradigm. In vitro, parvocellular neuroendocrine cells of the hypothalamic paraventricular nucleus recorded in slices from CVS rats showed an increase in basal excitatory synaptic inputs and a decrease in basal inhibitory synaptic inputs compared with neurons from control rats. There was no difference between control and CVS-treated rats in the rapid glucocorticoid suppression of excitatory synaptic inputs, a fast feedback mechanism. In vivo, CVS-treated rats showed an increase in ACTH secretion at baseline and after both iv CRH and acute stress and no impairment of the corticosterone suppression of the ACTH response, compared with controls. In an in vitro pituitary preparation, an increase in basal ACTH release, a small increase in CRH-induced ACTH release, and no decrement in the glucocorticoid suppression of ACTH release were seen in pituitaries from CVS rats. Thus, CVS does not suppress rapid glucocorticoid negative feedback at the hypothalamus or pituitary, but increases the synaptic excitability of paraventricular nucleus CRH neurons and the CRH sensitivity of the pituitary. Therefore, increased HPA activity in chronically stressed male rats is due to sensitization of the HPA axis, rather than to desensitization to rapid glucocorticoid feedback.