MR-guided focused ultrasound in pediatric neurosurgery: current insights, technical challenges, and lessons learned from 45 treatments at Children's National Hospital.

OBJECTIVE: MR-guided focused ultrasound (MRgFUS) is an evolving technology with numerous present and potential applications in pediatric neurosurgery. The aim of this study was to describe the use of MRgFUS, technical challenges, complications, and lessons learned at a single children's hospital. METHODS: A retrospective analysis was performed of a prospectively collected database of all pediatric patients undergoing investigational use of MRgFUS for treatment of various neurosurgical pathologies at Children's National Hospital. Treatment details, clinical workflow, and standard operating procedures are described. Patient demographics, procedure duration, and complications were obtained through a chart review of anesthesia and operative reports. RESULTS: In total, 45 MRgFUS procedures were performed on 14 patients for treatment of diffuse intrinsic pontine glioma (n = 12), low-grade glioma (n = 1), or secondary dystonia (n = 1) between January 2022 and April 2024. The mean age at treatment was 9 (range 5-22) years, and 64% of the patients were male. With increased experience, the total anesthesia time, sonication time, and change in core body temperature during treatment all significantly decreased. Complications affected 4.4% of patients, including 1 case of scalp edema and 1 patient with a postprocedure epidural hematoma. Device malfunction requiring abortion of the procedure occurred in 1 case (2.2%). Technical challenges related to transducer malfunction and sonication errors occurred in 6.7% and 11.1% of cases, respectively, all overcome by subsequent user modifications. CONCLUSIONS: The authors describe the largest series on MRgFUS technical aspects in pediatric neurosurgery at a single institution, comprising 45 total treatments. This study emphasizes potential technical challenges and provides valuable insights into the nuances of its application in pediatric patients.

The Spaghetti Sign: Nerve Root Redundancy in Lumbar Spinal Stenosis.

OBJECTIVE: Redundant nerve roots (RNRs) seen in conjunction with lumbar spinal stenosis (LSS) are well-described radiographic findings. Several studies suggest their presence may be a negative prognostic indicator of postoperative outcome. Our hypothesis was that severe RNR (informally known as the spaghetti sign [SS]) can serve as a reliable marker of LSS that would benefit from surgical decompression. We sought to evaluate a grading scale for RNR, characterize the association with stenosis, and investigate the clinical implications of RNR. METHODS: We conducted a retrospective chart review of 72 patients who underwent lumbar spine surgery from 2016 to 2018 at 1 institution. Preoperative T2 magnetic resonance imaging scans were graded by 3 reviewers for severity of stenosis (0-4), severity of RNR (0-3), and rostral versus caudal RNR. SS was defined as RNR score ≥2 (clear-cut or marked nerve root irregularity). Preoperative and postoperative Oswestry Disability Index scores were analyzed by stenosis and RNR severity. RESULTS: Seventy-one (98%) patients had severe stenosis (score ≥3) and 25 (35%) had a SS. SS was 100% specific for high-grade stenosis. If patients had a SS, it was more likely rostral (P=0.02). Postoperative Oswestry Disability Index scores improved significantly, but there were no differences related to RNR score, presence of SS, or stenosis severity. CONCLUSIONS: The study demonstrated that there is a significant association between SS and severe LSS and that presence of RNR is not a negative prognostic indicator for postoperative outcomes.

Positional aphasia as a manifestation of syndrome of the trephined: illustrative case.

BACKGROUND: The authors report a case of a 66-year-old male who presented acutely with a subdural hematoma who was managed operatively with craniotomy. His course was complicated by a postoperative epidural hematoma, which, on the basis of intraoperative findings at the second surgery, was managed with evacuation of the hematoma and removal of the bone flap. OBSERVATIONS: The patient's subsequent recovery was remarkable for a reproducible positional aphasia in the early postoperative period with an ultimate diagnosis of syndrome of the trephined. The patient's cerebral edema permitted early autologous cranioplasty, which resulted in resolution of the patient's symptoms. LESSONS: The authors believe this case to be the first described of isolated positional aphasia as a manifestation of syndrome of the trephined. Recognition and treatment of the syndrome resulted in a positive patient outcome.

Tectal Hemorrhage in the Setting of COVID-19 Infection.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has emerging evidence of a relationship to intracranial hemorrhage. The hemorrhages described to date often affect patients on anticoagulation, of advanced age, of nonwhite race, and requiring mechanical ventilation. Unusual or rare hemorrhage patterns have not as yet been described in the literature as being associated with COVID-19. CASE REPORT: A 36-year-old Hispanic male with no significant past medical history presented with isolated tectal intraparenchymal hemorrhage with intraventricular hemorrhage in the setting of no identifiable risk factors other than COVID-19. His management required temporizing with external ventricular drainage and subsequent endoscopic third ventriculostomy for ongoing obstruction of the cerebral aqueduct following the hemorrhage. He was discharged and did clinically well. To our knowledge, this is the first report of an intraparenchymal hematoma of the brain isolated to the midbrain tectum with only COVID-19 as a risk factor. CONCLUSION: COVID-19 may predispose patients to rare types of intraparenchymal hematomas which remain amenable to standard management algorithms.

Recrudescent infection after deep brain stimulator reimplantation.

OBJECTIVE: The efficacy of deep brain stimulation (DBS) in treating the symptoms of movement disorders can be life changing for patients. Thus, the 5%-15% incidence of stimulator-related infection requiring removal of the device can be particularly disheartening. Although DBS system reimplantation is generally successful, this is not always the case. The literature is replete with publications describing the incidence of infection and the associated features. However, the literature is sparse in terms of information on the incidence of recurrent or recrudescent infection after system reimplantation. The goal of this paper was to evaluate factors leading to unsuccessful reimplantation of a DBS system following initial infection. METHODS: Data were reviewed for all DBS procedures performed by one surgeon (K.L.H.) over 19 years including the infectious agent, location of infection, treatment regimen, and subsequent reimplantation of a DBS system and long-term outcome. RESULTS: In this series of 558 patients who had undergone DBS surgery, 37 (6.6%) subsequently developed an infection. Infections with methicillin-sensitive Staphylococcus aureus, Enterobacter species, or coagulase-negative staphylococci were predominant. Four patients had cerebritis, one had meningitis, and the rest had soft tissue infections of the pocket or scalp. All had their entire DBS system explanted, followed by 4-6 weeks of intravenous antibiotics and surveillance for recrudescence for an additional period of at least 30 days. Twenty-five patients subsequently underwent DBS system reimplantation, and the procedure was successful in 22. Three of the 4 patients with cerebritis developed a subsequent wound infection after system reimplantation. None of the other 22 patients developed a recurrence. The odds ratio for developing a recurrent infection after cerebritis was 28.5 (95% CI 1.931-420.5, p = 0.007). CONCLUSIONS: This study, the largest series of DBS system reimplantations following infection, demonstrated that most patients can have successful reimplantations without recurrent infection. However, patients who have had DBS-related cerebritis have a nearly 30-fold increased risk of developing reinfection after reimplantation. Alternative strategies for these patients are discussed.