✓Basicranial diastematomyelia is an extremely rare congenital disorder. A review of the literature indicates only one reported case of basicranial diastematomyelia in which an osseous peg divided the brainstem in two. The authors present the first reported case of basicranial diplomyelia split by a fibrous band and correlate its pathogenesis with that of split cord malformation (SCM). The patient described in the present report had a fibrous stalk dividing the brainstem, and therefore the condition was categorized as a diplomyelia, or SCM Type II. Because the occipital dermatomes behave similarly to the spinal dermatomes early in development, they may be subject to the same embryonic error that results in SCM. The authors propose that the mechanism leading to SCM is the same as that found in basicranial split malformations and that the theory explaining it be modified to include the posterior fossa.
Edward Rustamzadeh, Patrick C. Graupman, and Cornelius H. Lam
Margaret A. Wallenfriedman, John A. Conrad, Lance DelaBarre, Patrick C. Graupman, Gina Lee, Michael Garwood, Dale S. Gregerson, Walter C. Jean, Walter A. Hall, and Walter C. Low
Object. Glioblastoma multiforme (GBM) is a malignant tumor of the central nervous system that directly suppresses immunological defenses in vitro and in vivo. The authors used the peripheral delivery of continuously infused granulocyte—macrophage colony-stimulating factor (GM-CSF) in the presence of irradiated tumor antigens as a tumor-specific stimulant to dendritic cells to initiate an immune response to GBM in rats.
Methods. The 9L gliosarcoma tumors were established in the flanks of syngeneic Fischer 344 rats. Osmotic minipumps implanted in the animals' contralateral flanks continuously delivered recombinant GM-CSF (0, 0.1, 1, or 10 ng/day) for 28 days. Irradiated gliosarcoma cells were intermittently injected at the site of the GM-CSF infusion. Animals in the saline control group (0 ng/day GM-CSF) died on Day 59 with average tumor volumes greater than 30,000 mm3. This control group was significantly different from the GM-CSF—treated animals, which all survived with average tumor volumes that peaked on Day 23 and later regressed completely. Tumor growth as well as peak tumor volumes (5833 ± 2284 mm3, 3294 ± 1632 mm3, and 1979 ± 1142 mm3 for 0.1, 1, and 10 ng/day GM-CSF, respectively) in the different treatment groups reflected a significant dose-response relationship with the GM-CSF concentrations. All animals treated with GM-CSF and irradiated cells were resistant to additional challenges of peripheral and intracerebral gliosarcoma, even when they were inoculated 8 months after initial immunotherapy. The colocalization of GM-CSF and inactivated tumor antigens was required to stimulate immunoprotection. To test the efficacy of a peripherally administered immunological therapy on intracerebral brain tumors the authors transplanted 106 gliosarcoma cells into the striatum of treated and control animals. Subcutaneous pumps that released GM-CSF (10 ng/day) and irradiated gliosarcoma cells were placed in the treated animals. The control animals all died within 31 days after intracerebral tumor implantation. In contrast, 40% of the animals receiving GM-CSF—irradiated cell vaccinations survived beyond 300 days. These long-term survivors showed no evidence of gliosarcoma at the injection site on evaluation by magnetic resonance imaging.
Conclusions. These results suggest that the continuous localized delivery of subcutaneous GM-CSF in conjunction with inactivated tumor antigens can initiate a systemic response that leads to the regression of distant peripheral and intracerebral tumors. The success of this treatment illustrates the feasibility of tumor-specific peripheral immunological stimulation after tumor resection to prevent the recurrence of malignant brain tumors.
Alexander T. Yahanda, P. David Adelson, S. Hassan A. Akbari, Gregory W. Albert, Philipp R. Aldana, Tord D. Alden, Richard C. E. Anderson, David F. Bauer, Tammy Bethel-Anderson, Douglas L. Brockmeyer, Joshua J. Chern, Daniel E. Couture, David J. Daniels, Brian J. Dlouhy, Susan R. Durham, Richard G. Ellenbogen, Ramin Eskandari, Timothy M. George, Gerald A. Grant, Patrick C. Graupman, Stephanie Greene, Jeffrey P. Greenfield, Naina L. Gross, Daniel J. Guillaume, Todd C. Hankinson, Gregory G. Heuer, Mark Iantosca, Bermans J. Iskandar, Eric M. Jackson, James M. Johnston, Robert F. Keating, Mark D. Krieger, Jeffrey R. Leonard, Cormac O. Maher, Francesco T. Mangano, J. Gordon McComb, Sean D. McEvoy, Thanda Meehan, Arnold H. Menezes, Brent R. O’Neill, Greg Olavarria, John Ragheb, Nathan R. Selden, Manish N. Shah, Chevis N. Shannon, Joshua S. Shimony, Matthew D. Smyth, Scellig S. D. Stone, Jennifer M. Strahle, James C. Torner, Gerald F. Tuite, Scott D. Wait, John C. Wellons III, William E. Whitehead, Tae Sung Park, and David D. Limbrick Jr.
Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM.
The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft.
A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain.
In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.
Andrew T. Hale, P. David Adelson, Gregory W. Albert, Philipp R. Aldana, Tord D. Alden, Richard C. E. Anderson, David F. Bauer, Christopher M. Bonfield, Douglas L. Brockmeyer, Joshua J. Chern, Daniel E. Couture, David J. Daniels, Susan R. Durham, Richard G. Ellenbogen, Ramin Eskandari, Timothy M. George, Gerald A. Grant, Patrick C. Graupman, Stephanie Greene, Jeffrey P. Greenfield, Naina L. Gross, Daniel J. Guillaume, Gregory G. Heuer, Mark Iantosca, Bermans J. Iskandar, Eric M. Jackson, James M. Johnston, Robert F. Keating, Jeffrey R. Leonard, Cormac O. Maher, Francesco T. Mangano, J. Gordon McComb, Thanda Meehan, Arnold H. Menezes, Brent O’Neill, Greg Olavarria, Tae Sung Park, John Ragheb, Nathan R. Selden, Manish N. Shah, Matthew D. Smyth, Scellig S. D. Stone, Jennifer M. Strahle, Scott D. Wait, John C. Wellons, William E. Whitehead, Chevis N. Shannon, David D. Limbrick Jr., and for the Park-Reeves Syringomyelia Research Consortium Investigators
Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established.
Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length.
The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16–0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34–1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12–0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02–2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31–3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67–5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate.
These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.