Suboccipital craniectomy with duraplasty is a commonly performed procedure for children with symptomatic Chiari malformation type I (CM-I). Several dural substitutes are used for duraplasty, ranging from pericranium to synthetic materials. When available, autologous pericranium is often preferred due to its low cost, performance in obtaining a watertight closure, ease of suturing, and absence of immune reaction. Long-term follow-up data on the durability of various dural substitutes are lacking. The authors report a rare, long-term complication of duraplasty performed using an autologous pericranial graft, and they conduct a literature review of similar complications. Heterotopic ossification of an autologous pericranial graft is a rare complication of duraplasty. This dystrophic bone growth can be symptomatic due to compression of neural structures, and it requires reoperation for removal. Surgeons should consider this rare long-term complication in patients presenting with unusual symptoms after duraplasty with pericranium.
Christopher E. Louie, Jennifer Hong, and David F. Bauer
Jo Ling Goh, David F. Bauer, Susan R. Durham, and Mitchell A. Stotland
The goal of this study was to review the current literature on orthotic (helmet) therapy use in the treatment of deformational plagiocephaly.
PubMed was used to search English articles using the medical subject headings “deformational plagiocephaly” and “orthosis,” and “deformational plagiocephaly” and “helmet.”
Forty-two articles were found. There were no Class I studies, 7 Class II studies, 1 Class III study, and 13 Class IV studies. Cranial orthoses have been shown to be effective in treating deformational plagiocephaly. It continues to be debated as to whether the statistical significance of treatment with cranial orthoses compared with conservative therapies is clinically significant. Children older than 12 months of age with deformational plagiocephaly may still benefit from orthotic therapy. The long-term effects of orthotic therapy are controversial.
There is a lack of Class I literature evidence supporting the use of helmet therapy in deformational plagiocephaly. There are controversies surrounding the use of orthotic therapy such as appropriate use, cost, use in older children, and long-term outcomes. Clinical indications for orthotic therapy need to be better defined with further research studies.
Wesley J. Whitson, Jessica R. Lane, David F. Bauer, and Susan R. Durham
Chiari malformation Type I (CM-I) in children is a common incidental finding. Resolution of cerebellar tonsil ectopia has been reported, but no studies have followed tonsil position over regular intervals throughout childhood. To better elucidate the clinical and radiological natural history of CM-I in children, the authors prospectively followed up children with nonoperatively managed CM-I for up to 7 years.
The study included all children evaluated for CM-I over a period of 12 years for whom surgery was not initially recommended. The study excluded patients with associated conditions, including syringomyelia and hydrocephalus. For all patients, initial management was nonoperative, and follow-up management consisted of annual cervical spine or brain MRI and clinical examination. At each follow-up examination, the neurological examination findings, subjective symptoms, and the position of the cerebellar tonsils on MR images were recorded. An alteration in tonsillar descent of 2 mm or greater was considered a change.
Neurological examination findings did not change over the course of the study in the 52 children who met the inclusion criteria. Although radiological changes were common, no surgeries were performed solely because of radiological change. Overall, tonsil position on radiological images remained stable in 50% of patients, was reduced in 38%, and increased in 12%. Resolution was seen in 12% of patients. Radiological changes in tonsil position were seen during every year of follow-up. On average, in any given year, 24% of images showed some form of change in tonsil position. A total of 3 patients, for whom no changes were seen on MR images, ultimately underwent surgery for subjective clinical reasons.
CM-I in children is not a radiologically static entity but rather is a dynamic one. Radiological changes were seen throughout the 7 years of follow-up. A reduction in tonsillar descent was substantially more common than an increase. Radiological changes did not correlate with neurological examination finding changes, symptom development, or the need for future surgery. Follow-up imaging of asymptomatic children with CM-I did not alter treatment for any patient. It would be reasonable to follow these children with clinical examinations but without regular surveillance MRI.
Erin D’Agostino, Daniel R. Calnan, William Hickey, and David F. Bauer
Intracranial collision tumors have rarely been reported in the literature and generally include at least 1 malignant tumor component. Subependymoma with dysembryoplastic neuroepithelial tumor (DNET) is an as-yet unreported combination. Both components are uncommon tumors, and presentation in the foramen of Monro is even more unusual. A 16-year-old male patient with a past medical history significant for asthma presented with a 3-month history of headaches and radiographic evidence of mild obstructive hydrocephalus secondary to a nonenhancing ventricular lesion at the foramen of Monro. He underwent endoscopic biopsy and resection. Pathological analysis revealed distinct components of subependymoma and DNET. At the 1-year follow-up, the patient was doing well without regrowth of tumor. The authors describe a case of intracranial collision tumor demonstrating 2 grade I components: a novel combination of subependymoma and DNET.
Terrance M. Darcey, Erik J. Kobylarz, Michael A. Pearl, Patricia J. Krauss, Stephanie A. Ferri, David W. Roberts, and David F. Bauer
The purpose of this study was to develop safe, site-specific procedures for placing and leaving subdermal needle leads for intraoperative monitoring (IOM) during intraoperative MRI procedures.
The authors tested a variety of standard subdermal needle electrodes designed and FDA-approved for IOM in the conventional operating room. Testing was used to determine the conditions necessary to avoid thermal injury and significant image artifacts with minimal disruption of IOM and MRI procedures. Phantom testing was performed with a fiber optic (lead) temperature monitoring system and was followed by testing of leads placed in a healthy volunteer. The volunteer testing used electrode placements typical of standard IOM cases, together with radiofrequency (RF) coil placement and imaging sequences routinely employed for these case types. Lead length was investigated to assess heating effects for electrodes placed within the RF coil.
The authors found that conventional stainless steel (SS) and platinum/iridium (Pt/Ir) subdermal needles can be used safely without significant heating when placed outside the RF coil, and this accounts for the majority or entirety of electrode placements. When placed within the RF coil, Pt/Ir leads produced minimal image artifacts, while SS leads produced potentially significant artifacts. In phantom testing, significant heating was demonstrated in both SS and Pt/Ir leads placed within the RF coil, but only during high-resolution T2-weighted scanning. This problem was largely, but not completely, eliminated when leads were shortened to 25 cm. Human testing was unremarkable except for nonpainful heating detected in a few electrodes during thin-slice (1.5 mm) FLAIR scanning. Transient irritation (skin reddening along the needle tract) was noted at 2 of the electrodes with detectable heating.
The authors were satisfied with the safety of their site-specific procedures and have begun with off-label use (following institutional review board approval and obtaining patient informed consent) of tested monitoring leads in cases that combine IOM and MRI. The authors recommend that all facilities perform their own site-specific testing of monitoring leads before proceeding with their routine use.
Wesley J. Whitson, Perry A. Ball, S. Scott Lollis, Jason D. Balkman, and David F. Bauer
Mycoplasma hominis is a rare cause of infection after neurosurgical procedures. The Mycoplasma genus contains the smallest bacteria discovered to date. Mycoplasma are atypical bacteria that lack a cell wall, a feature that complicates both diagnosis and treatment. The Gram stain and some types of culture media fail to identify these organisms, and typical broad-spectrum antibiotic regimens are ineffective because they act on cell wall metabolism. Mycoplasma hominis commonly colonizes the genitourinary tract in a nonvirulent manner, but it has caused postoperative, postpartum, and posttraumatic infections in various organ systems.
The authors present the case of a 17-year-old male with a postoperative intramedullary spinal cord abscess due to M. hominis and report the results of a literature review of M. hominis infections after neurosurgical procedures. Attention is given to time to diagnosis, risk factors for infection, ineffective antibiotic regimens, and final effective antibiotic regimens to provide pertinent information for the practicing neurosurgeon to diagnose and treat this rare occurrence.
A PubMed search was performed to identify reports of M. hominis infections after neurosurgical procedures.
Eleven cases of postneurosurgical M. hominis infection were found. No other cases of intramedullary spinal cord abscess were found. Initial antibiotic coverage was inadequate in all cases, and diagnosis was delayed in all cases. Multiple surgical interventions were often needed. Once appropriate antibiotics were started, patients typically experienced rapid resolution of their neurological symptoms. In 27% of cases, a suspicious genitourinary source other than urinary catheterization was identified.
Postoperative M. hominis infections are rarely seen after neurosurgical procedures. They are typically responsive to appropriate antibiotic therapy. Mycoplasma infection may cause prolonged hospitalization and multiple returns to the operating room due to delay in diagnosis. Early clinical suspicion with appropriate antibiotic coverage could help prevent these significant complications.
Hena Waseem, Rachael S. Mazzamurro, Alec H. Fisher, Subasish Bhowmik, Rifat A. Zaman, Angeline Andrew, and David F. Bauer
Parental presence in the operating room during the induction of anesthesia (PPIA) has been shown to decrease parent and child anxiety and increase satisfaction with patient experience in outpatient otolaryngological procedures, such as tympanostomy tube placement. PPIA for other procedures, such as a major neurosurgical intervention, has been a practice at the authors’ institutions for many years. This practice is not universally accepted across the United States, and the potential benefits for patients and families have not been formally evaluated. The aim of this study is to provide a qualitative analysis of parental and patient satisfaction with PPIA at the authors’ institution.
All patients younger than 18 years who underwent surgical intervention at the authors’ institution between August 2013 and December 2015 were identified. All surgeries were performed by a single neurosurgeon. A random sample of 96 parents were contacted by telephone for a qualitative, semiscripted interview; 42 parents completed the interviews. The interview consisted of a validated satisfaction assessment in addition to a standardized open-ended questionnaire. Thematic analysis was performed until saturation was achieved, and responses were coded into the predominant themes. Member checking was performed, and a thick description was created.
The predominant themes identified with PPIA were 1) perception of induction as traumatizing or distressing to witness, 2) positive feelings regarding having been present, 3) satisfaction regarding the overall experience with surgery, 4) variable feelings in parents who decided not to attend induction, and 5) mixed feelings in the interactions with the care team. Parents expressed an array of positive, negative, and neutral impressions of the experience; however, overall, most experiences were positive. Most parents would choose PPIA again if their child required additional surgery.
This is the first study to evaluate the benefit of PPIA for pediatric neurosurgical patients. The results show a unique insight into medical communication and patient satisfaction with high-risk surgeries. PPIA may be able to help shape an environment of trust and increase satisfaction with perioperative care.
Presented at the 2013 Joint Spine Section Meeting
Christoph J. Griessenauer, David F. Bauer, Thomas A. Moore II, Patrick R. Pritchard, and Mark N. Hadley
Various pathologies involving the thoracic arachnoid mater uniformly manifest as thoracic myelopathy and may present a significant management dilemma. The authors undertook this study to assess outcome in cases of thoracic myelopathy due to thoracic arachnoid pathology.
The authors have cared for and followed 28 patients with thoracic myelopathy from thoracic arachnoid pathology over the last 17 years. A chart review and contemporary follow-up of these patients was performed and outcomes were reported.
Patients with thoracic myelopathy from thoracic arachnoid pathology often have improvement in their condition after surgical decompression/detethering procedures. While not universal, patients in this series had improvement in mJOA scores at 1 year after surgery (p = 0.0001) and at last follow-up (p = 0.04). Results indicated that across a wide variety of pathologies the extent of thoracic spinal cord involvement is a predictor of the disease course and outcome. Comparison of the group of patients with cord involvement limited to 2 vertebral segments (short-segment pathology) versus the group with cord tethering of more than 2 segments (long-segment pathology) showed that patients in the short-segment group more frequently had ventral or dorsal arachnoid bands (p = 0.003), more frequently had signal change in the cord on MRI (p = 0.02), and less frequently presented with a syrinx (p = 0.02), and a smaller percentage of patients in this group underwent reoperation (p = 0.02). While patients with short-segment pathology typically improved after a single operative intervention, patients with long-segment pathology typically improved after multiple operations, frequently for CSF diversion.
Thoracic arachnoid pathology causing thoracic cord dysfunction and myelopathy is varied, has multiple etiologies, and can be difficult to treat over the long term. Surgical management, when indicated, is case specific. Serial long-term follow-up is essential to document enduring clinical and radiographic success.
Linton T. Evans, Jack Van Hoff, William F. Hickey, Miriam J. Smith, D. Gareth Evans, William G. Newman, and David F. Bauer
Clear cell meningioma (CCM) is an uncommon variant of meningioma. The authors describe a case of a pediatric CCM localized to the lumbar spine. After resection, sequencing revealed an inactivating mutation in the SWI/SNF chromatin remodeling complex subunit SMARCE1, with loss of the second allele in the tumor. The authors present a literature review of this mutation that is associated with CCM and a family history of spine tumors.