En bloc spinal tumor resections are technically demanding procedures with high morbidity because of the conventionally large exposure area and aggressive resection goals. Stereotactic surgical navigation presents an opportunity to perform the smallest possible resection plan while still achieving an en bloc resection. Augmented reality (AR)–mediated spine surgery (ARMSS) via a mounted display with an integrated tracking camera is a novel FDA-approved technology for intraoperative “heads up” neuronavigation, with the proposed advantages of increased precision, workflow efficiency, and cost-effectiveness. As surgical experience and capability with this technology grow, the potential for more technically demanding surgical applications arises. Here, the authors describe the use of ARMSS for guidance in a unique osteotomy execution to achieve an en bloc wide marginal resection of an L1 chordoma through a posterior-only approach while avoiding a tumor capsule breach. A technique is described to simultaneously visualize the navigational guidance provided by the contralateral surgeon’s tracked pointer and the progress of the BoneScalpel aligned in parallel with the tracked instrument, providing maximum precision and safety. The procedure was completed by reconstruction performed with a quad-rod and cabled fibular strut allograft construct, and the patient did well postoperatively. Finally, the authors review the technical aspects of the approach, as well as the applications and limitations of this new technology.
Camilo A. Molina, Christopher F. Dibble, Sheng-fu Larry Lo, Timothy Witham, and Daniel M. Sciubba
Hiroki Hori, Hirokazu Iwamuro, Masayuki Nakano, Takahiro Ouchi, Takashi Kawahara, Takaomi Taira, Keiichi Abe, Ken Iijima, and Toshio Yamaguchi
OBJECTIVE
In transcranial magnetic resonance imaging–guided focused ultrasound (TcMRgFUS), a high skull density ratio (SDR) is advantageous to achieve a sufficiently high temperature at the target. However, it is not easy to estimate the temperature rise because the SDR shows different values depending on the reconstruction filter used. The resolution characteristic of a computed tomography (CT) image depends on a modulation transfer function (MTF) defined by the reconstruction filter. Differences in MTF induce unstable SDRs. The purpose of this study was both to standardize SDR by developing a method to correct the MTF and to enable effective patient screening prior to TcMRgFUS treatment and more accurate predictions of focal temperature.
METHODS
CT images of a skull phantom and five subjects were obtained using eight different reconstruction filters. A frequency filter (FF) was calculated using the MTF of each reconstruction filter, and the validity of SDR standardization was evaluated by comparing the variation in SDR before and after FF correction. Subsequently, FF processing was similarly performed using the CT images of 18 patients who had undergone TcMRgFUS, and statistical analyses were performed comparing the relationship between the SDRs before and after correction and the maximum temperature in the target during TcMRgFUS treatment.
RESULTS
The FF was calculated for each reconstruction filter based on one manufacturer's BONE filter. In the CT images of the skull phantom, the SDR before FF correction with five of the other seven reconstruction filters was significantly smaller than that with the BONE filter (p < 0.01). After FF correction, however, a significant difference was recognized under only one condition. In the CT images of the five subjects, variation of the SDR due to imaging conditions was significantly improved after the FF correction. In 18 cases treated with TcMRgFUS, there was no correlation between SDR before FF correction and maximum temperature (rs = 0.31, p > 0.05); however, a strong positive correlation was observed after FF correction (rs = 0.71, p < 0.01).
CONCLUSIONS
After FF correction, the difference in SDR due to the reconstruction filter used is smaller, and the correlation with temperature is stronger. Therefore, the SDR can be standardized by applying the FF, and the maximum temperature during treatment may be predicted more accurately.
Stephen T. Magill, John A. Jane Jr., and Daniel M. Prevedello
Theodore H. Schwartz and Michael W. McDermott
Ananya Chakravorty, Ronald T. Murambi, and Ravi Kumar V. Cherukuri
Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, also known as pseudogout, is a crystalline arthropathy that usually affects large joints and periarticular tissue. Spinal involvement is rare and is usually limited to extradural articular and periarticular structures. Only one case of intradural disease has been previously reported. The authors report the second known case of intradural CPPD deposition disease. An 81-year-old man presented with an 8-week history of urinary and fecal incontinence on the background of long-standing back pain, lower-limb paresthesia, and a known L1 calcified intradural extramedullary mass. Slow growth of the L1 lesion had been documented over several decades on serial CT and MRI. A T12–L2 laminectomy and gross-total resection of the mass was performed. Histopathology demonstrated polarizing rhomboid-shaped crystals consistent with CPPD deposition disease. The patient had significant improvement in bowel and bladder function 6 months postoperatively and made a full recovery. The pathophysiology of intradural involvement remains uncertain. Further case series are required to clarify the true incidence and prognosis of the condition.
Victor Vakayil, Jeremiah Atkinson, Vikram Puram, James J. Glover, James V. Harmon, Catherine L. Statz, David W. Polly Jr., and Robert E. Bulander
OBJECTIVE
Surgical site infection (SSI) following spine surgery is associated with increased morbidity and healthcare costs. In an effort to reduce SSI rates, the application of intrawound vancomycin powder has gained popularity. However, there is limited high-quality evidence to support the safety and efficacy of this practice. The authors sought to determine if intrawound application of vancomycin powder improves 90-day overall SSI rates.
METHODS
The authors performed a retrospective, vancomycin exposure–matched cohort study at a single tertiary care hospital over 21 months. They included all patients undergoing elective spinal surgery and stratified the patients into two groups: those who received intrawound vancomycin powder application and those who received no application of vancomycin powder. The primary outcome of interest was the 90-day overall SSI rate. Secondary outcomes included rates of superficial SSI, deep SSI, wound disruption, and a post hoc analysis of the microbiology and minimum inhibitory concentrations. Baseline patient demographics, clinical presentation, comorbidities, perioperative factors, and 90-day postoperative outcomes were manually abstracted from patient charts. To mitigate bias, we performed 1:1 matching after calculating propensity scores and identified 1 patient from the no-vancomycin cohort for each patient in the vancomycin cohort.
RESULTS
A total of 997 patients met our inclusion criteria (473 patients receiving vancomycin and 524 patients not receiving vancomycin). Propensity score matching produced 221 matched pairs. Risk-adjusted analysis demonstrated similar overall SSI rates between the groups (OR 1.9, p = 0.329). On unadjusted analysis, the overall 90-day SSI rate was greater in the vancomycin group (n = 10 [4.5%]) than in the no-vancomycin group (n = 5 [2.3%]) (p < 0.001), as were the superficial SSI rate (7 [3.2%] vs 4 [1.8%], p < 0.001), deep SSI rate (3 [1.4%] vs 1 [0.5%], p < 0.001), and wound disruption rate (5 [2.3%] vs 1 [0.5%], p < 0.001). No cultured isolate demonstrated vancomycin resistance.
CONCLUSIONS
The authors observed no difference in SSI rates after the intrawound application of vancomycin powder during spine surgery. Vancomycin use did not contribute to antimicrobial resistance; however, it may select out gram-negative bacteria and increase rates of wound disruption.
Mohammed A. Fouda, Madeline Karsten, Steven J. Staffa, R. Michael Scott, Karen J. Marcus, and Lissa C. Baird
OBJECTIVE
The goal of this study was to identify the independent risk factors for recurrence or progression of pediatric craniopharyngioma and to establish predictors of the appropriate timing of intervention and best management strategy in the setting of recurrence/progression, with the aim of optimizing tumor control.
METHODS
This is a retrospective cohort study of all pediatric patients with craniopharyngioma who were diagnosed and treated at Boston Children’s Hospital between 1990 and 2017. This study was approved by the institutional review board at Boston Children’s Hospital. All statistical analyses were performed using Stata software.
RESULTS
Eighty patients (43 males and 37 females) fulfilled the inclusion criteria. The mean age at the time of diagnosis was 8.6 ± 4.4 years (range 1.2–19.7 years). The mean follow-up was 10.9 ± 6.5 years (range 1.3–24.6 years). Overall, 30/80 (37.5%) patients developed recurrence/progression. The median latency to recurrence/progression was 12.75 months (range 3–108 months). Subtotal resection with no adjuvant radiotherapy (p < 0.001) and fine calcifications (p = 0.008) are independent risk factors for recurrence/progression. An increase (%) in the maximum dimension of the tumor at the time of recurrence/progression was considered a statistically significant predictor of the appropriate timing of intervention.
CONCLUSIONS
Based on the identified independent risk factors for tumor recurrence/progression and the predictors of appropriate timing of intervention in the setting of recurrence/progression, the authors propose an algorithm for optimal management of recurrent pediatric craniopharyngioma to increase the likelihood of tumor control.
Ghazaleh Kheiri, Negin Naderian, Sajedeh Karami, Zohreh Habibi, and Farideh Nejat
OBJECTIVE
Prenatal ventriculomegaly is classified as mild, moderate, or severe based on the atrium diameter. The natural course and intrauterine progression of mild and moderate ventriculomegaly associated with the neurodevelopmental status of these children has been widely reported.
METHODS
One hundred twenty-two pregnancies with mild and moderate ventriculomegaly referred to the pediatric neurosurgery clinic of Children’s Medical Center between 2010 and 2018 were retrospectively studied. The authors collected demographic and first and sequential ultrasonographic information, associated abnormalities, information about pregnancy outcomes, and the latest developmental status of these children according to Centers for Disease Control and Prevention criteria by calling parents at least 1 year after birth.
RESULTS
The mean gestational age at the time of diagnosis was 29.1 weeks, and 53% of fetuses were female. The width of the atrium was registered precisely in 106 cases, in which 61% had mild and 39% had moderate ventriculomegaly. Information on serial ultrasound scans was collected in 84 cases in which ventriculomegaly regressed in 5, remained stable in 67, and progressed in 12 patients. Fourteen cases (29.7%) in the mild ventriculomegaly group and 6 cases (16.2%) in the moderate group had associated abnormalities, with corpus callosum agenesis as the most frequent abnormality. The survival rate was 80% in mild and 89.4% in moderate ventriculomegaly. Considering survival to live birth and progression of the ventriculomegaly, the survival rate was 100% in regressed, 97% in stable, and 41.6% in progressed ventricular width groups (p < 0.001). Neurodevelopmental status was evaluated in 73 cases and found to be normal in 69.8% of the cases; 16.4% of children had mild delay, and 5.4% and 8.2% of cases were diagnosed with moderate and severe delays, respectively.
CONCLUSIONS
In spite of a high rate of missed data in our retrospective study, most patients with mild or moderate ventriculomegaly had a stable or regressed course. Most cases had near-normal developmental status. Prospective studies with a larger sample size and detailed developmental evaluation tests are needed to answer the questions related to the natural course, survival, and prognosis of prenatal ventriculomegaly.
Tao Yang, Kazumichi Yoshida, Takakuni Maki, Yasutaka Fushimi, Kiyofumi Yamada, Masakazu Okawa, Yu Yamamoto, Naoki Takayama, Keita Suzuki, and Susumu Miyamoto
OBJECTIVE
Carotid webs (CWs) have increasingly been recognized as a cause of recurrent ischemic stroke. However, the natural history and clinical course of CWs remain unclear. The authors aimed to clarify the prevalence, imaging features, and optimal treatment of CWs in a Japanese cohort study.
METHODS
A series of 444 consecutive Japanese patients who had undergone CTA of the head and neck between April 2011 and October 2016 was retrospectively reviewed. CW was diagnosed on CT angiograms as a membrane-like intraluminal filling defect along the posterior wall of the carotid bulb or the origin of the internal carotid artery (ICA) on oblique sagittal images and a corresponding thin septum on axial images.
RESULTS
Two patients with CWs were identified among 132 patients with suspected stroke. The prevalence of CWs among symptomatic patients with suspected stroke was 1.5%. The prevalence of asymptomatic CWs was 2.2% (7 of 312 cases). The CWs were located in the posterior wall of the carotid bulb in 7 patients and just distal to the ICA origin in 2 patients. There were no apparent differences in the location or lesion length between symptomatic and asymptomatic CWs. Four of the 7 asymptomatic CWs remained asymptomatic for at least 2 years of follow-up. Two patients with symptomatic CWs developed recurrent cerebral infarction and transient ischemic attack despite being on a regimen of oral antiplatelet agents, and carotid endarterectomy was performed as radical treatment. Patients with CWs were younger than controls (median age 55 vs 69 years, p = 0.003) and were less frequently male than controls (33% vs 72%, p = 0.025). CW cases showed significantly fewer common atherosclerosis risk factors than the control group (p < 0.05).
CONCLUSIONS
Although limited to CTA patients, this study reported on the prevalence and common site of CWs, focusing on symptomatic and asymptomatic Japanese patients. Extensive cross-sectional and prospective observational studies are warranted to elucidate the overall prevalence and natural history of CWs.
Hongru Ma, Benlong Shi, Yang Li, Dun Liu, Zhen Liu, Xu Sun, Yong Qiu, and Zezhang Zhu
OBJECTIVE
The aim of this study was to compare the radiological and clinical outcomes of early-onset scoliosis (EOS) patients with or without intraspinal anomalies (IAs) managed with growing rods (GRs), and to evaluate the safety of the GR technique in EOS patients with untreated IAs.
METHODS
EOS patients undergoing GR placement between August 2008 and July 2017 were retrospectively reviewed. Patients with untreated IAs were classified into the EOS+IA group, and those without IAs into the EOS−IA group. The radiographic parameters including Cobb angle of the major curve, T1–S1 height, and apical vertebral translation were measured, and a detailed assessment of the neurological status was performed at each visit.
RESULTS
Seventy-six patients with EOS (32 boys, 44 girls) with an average age of 6.5 ± 2.3 years at initial surgery satisfied the inclusion and exclusion criteria, including 28 patients in the EOS+IA group and 48 patients in the EOS−IA group. The radiographic measurements were comparable between groups preoperatively, postoperatively, and at the latest follow-up. One patient in the EOS+IA group experienced sensory deficit in a unilateral lower extremity after initial surgery, and an intraoperative neurophysiological monitoring event was observed in a patient in the EOS−IA group. No permanent neurological deficit was observed in either group.
CONCLUSIONS
EOS patients with and those without IAs had comparable clinical and radiological outcomes of the GR technique. Repeated lengthening procedures may be safe for EOS patients with untreated IAs.
