Patrick W. Hitchon, Mario Zanaty, Logan Helland, Kingsley Abode-Iyamah, and Nader S. Dahdaleh
Arnold H. Menezes, Jeremy D. W. Greenlee, Reid A. Longmuir, Daniel R. Hansen, and Kingsley Abode-Iyamah
The authors present the case of a 14-year-old boy with holocord syringohydromyelia extending into the brainstem, cerebral peduncle, internal capsule, and cerebral cortex. At the posterior fossa exploration, an opaque thickened arachnoid with occlusion of the foramen of Magendie was encountered. Careful documentation of postoperative regression of the syringocephaly, syringobulbia, and syringohydromyelia was made. The pathophysiology is discussed.
Timothy E. Lindley, Nader S. Dahdaleh, Arnold H. Menezes, and Kingsley O. Abode-Iyamah
Management of pediatric occipitocervical instability remains especially challenging. The off-label use of recombinant human bone morphogenetic protein (rhBMP)-2 for spinal fusion has increased with a well-documented increase in fusion rate in many case series. Unfortunately, recent reports have documented complications associated with rhBMP use in adult spinal fusions. Complications associated with the use of rhBMP in pediatric spinal surgery is less well understood. In this study the authors report on the fusion rate and complications associated with rhBMP in pediatric occipitocervical arthrodesis.
The authors reviewed the medical records of those patients 18 years old and younger who underwent dorsal occipitocervical fusion from January 2004 to December 2007 at the University of Iowa Hospitals and Clinics. Forty-eight patients were identified who received rhBMP-augmented fusion. The clinical outcome and complications of these fusions were analyzed.
All 48 patients had fusion confirmed on lateral radiographs within 4–14 months with an average fusion time of 6.7 months. There were 6 complications, 5 of which included seroma formation. Two of 5 patients who developed postoperative seroma presented with symptoms suggesting brainstem compression and obstructive hydrocephalus requiring emergency reoperation. One patient developed heterotopic bone formation causing cervicomedullary compression requiring reoperation.
The use of rhBMP to augment autograft in occipitocervical fusion allows for a high rate of successful arthrodesis, but is associated with potentially life-threatening complications in pediatric patients.
Vincent C. Traynelis, Kingsley O. Abode-Iyamah, Katie M. Leick, Sarah M. Bender, and Jeremy D. W. Greenlee
The primary goal of this study was to review the immediate postoperative neurological function in patients surgically treated for symptomatic cervical spine disease without intraoperative neurophysiological monitoring. The secondary goal was to assess the economic impact of intraoperative monitoring (IOM) in this patient population.
This study is a retrospective review of 720 consecutively treated patients who underwent cervical spine procedures. The patients were identified and the data were collected by individuals who were not involved in their care.
A total of 1534 cervical spine levels were treated in 720 patients using anterior, posterior, and combined (360°) approaches. Myelopathy was present preoperatively in 308 patients. There were 185 patients with increased signal intensity within the spinal cord on preoperative T2-weighted MR images, of whom 43 patients had no clinical evidence of myelopathy. Three patients (0.4%) exhibited a new neurological deficit postoperatively. Of these patients, 1 had a preoperative diagnosis of radiculopathy, while the other 2 were treated for myelopathy. The new postoperative deficits completely resolved in all 3 patients and did not require additional treatment. The Current Procedural Terminology (CPT) codes for IOM during cervical decompression include 95925 and 95926 for somatosensory evoked potential monitoring of the upper and lower extremities, respectively, as well as 95928 and 95929 for motor evoked potential monitoring of the upper and lower extremities. In addition to the charge for the baseline [monitoring] study, patients are charged hourly for ongoing electrophysiology testing and monitoring using the CPT code 95920. Based on these codes and assuming an average of 4 hours of monitoring time per surgical case, the savings realized in this group of patients was estimated to be $1,024,754.
With the continuing increase in health care costs, it is our responsibility as providers to minimize expenses when possible. This should be accomplished without compromising the quality of care to patients. This study demonstrates that decompression and reconstruction for symptomatic cervical spine disease without IOM may reduce the cost of treatment without adversely impacting patient safety.
Timothy W. Vogel, Calvin S. Carter, Kingsley Abode-Iyamah, Qihong Zhang, and Shenandoah Robinson
Neural tube defects (NTDs) are a set of disorders that occur from perturbation of normal neural development. They occur in open or closed forms anywhere along the craniospinal axis and often result from a complex interaction between environmental and genetic factors. One burgeoning area of genetics research is the effect of cilia signaling on the developing neural tube and how the disruption of primary cilia leads to the development of NTDs. Recent progress has implicated the hedgehog (Hh), wingless-type integration site family (Wnt), and planar cell polarity (PCP) pathways in primary cilia as involved in normal neural tube patterning. A set of disorders involving cilia function, known as ciliopathies, offers insight into abnormal neural development. In this article, the authors discuss the common ciliopathies, such as Meckel-Gruber and Joubert syndromes, that are associated with NTDs, and review cilia-related signaling cascades responsible for mammalian neural tube development. Understanding the contribution of cilia in the formation of NTDs may provide greater insight into this common set of pediatric neurological disorders.
Kirsten E. Stoner, Kingsley O. Abode-Iyamah, Vincent A. Magnotta, Matthew A. Howard III, and Nicole M. Grosland
Cervical myelopathy (CM) is a common and debilitating form of spinal cord injury caused by chronic compression; however, little is known about the in vivo mechanics of the healthy spinal cord during motion and how these mechanics are altered in CM. The authors sought to measure 3D in vivo spinal cord displacement and strain fields from MR images obtained during physiological motion of healthy individuals and cervical myelopathic patients.
Nineteen study participants, 9 healthy controls and 10 CM patients, were enrolled in the study. All study participants had 3T MR images acquired of the cervical spine in neutral, flexed, and extended positions. Displacement and strain fields and corresponding principal strain were obtained from the MR images using image registration.
The healthy spinal cord displaces superiorly in flexion and inferiorly in extension. Principal strain is evenly distributed along the spinal cord. The CM spinal cord displaces less than the healthy cord and the magnitude of principal strain is higher, at the midcervical levels.
Increased spinal cord compression during cervical myelopathy limits motion of the spinal cord and increases spinal cord strain during physiological motion. Future studies are needed to investigate how treatment, such as surgical intervention, affects spinal cord mechanics.
Beejal Y. Amin and Praveen V. Mummaneni
Ravi Sharma, Manoj Phalak, and Varidh Katiyar
Anthony L. Mikula, Jeremy L. Fogelson, Soliman Oushy, Zachariah W. Pinter, Pierce A. Peters, Kingsley Abode-Iyamah, Arjun S. Sebastian, Brett Freedman, Bradford L. Currier, David W. Polly, and Benjamin D. Elder
Pelvic incidence (PI) is a commonly utilized spinopelvic parameter in the evaluation and treatment of patients with spinal deformity and is believed to be a fixed parameter. However, a fixed PI assumes that there is no motion across the sacroiliac (SI) joint, which has been disputed in recent literature. The objective of this study was to determine if patients with SI joint vacuum sign have a change in PI between the supine and standing positions.
A retrospective chart review identified patients with a standing radiograph, supine radiograph, and CT scan encompassing the SI joints within a 6-month period. Patients were grouped according to their SI joints having either no vacuum sign, unilateral vacuum sign, or bilateral vacuum sign. PI was measured by two independent reviewers.
Seventy-three patients were identified with an average age of 66 years and a BMI of 30 kg/m2. Patients with bilateral SI joint vacuum sign (n = 27) had an average absolute change in PI of 7.2° (p < 0.0001) between the standing and supine positions compared to patients with unilateral SI joint vacuum sign (n = 20) who had a change of 5.2° (p = 0.0008), and patients without an SI joint vacuum sign (n = 26) who experienced a change of 4.1° (p = 0.74). ANOVA with post hoc Tukey test showed a statistically significant difference in the change in PI between patients with the bilateral SI joint vacuum sign and those without an SI joint vacuum sign (p = 0.023). The intraclass correlation coefficient between the two reviewers was 0.97 for standing PI and 0.96 for supine PI (p < 0.0001).
Patients with bilateral SI joint vacuum signs had a change in PI between the standing and supine positions, suggesting there may be increasing motion across the SI joint with significant joint degeneration.
Kingsley O. Abode-Iyamah, Hsiu-Yin Chiang, Nolan Winslow, Brian Park, Mario Zanaty, Brian J. Dlouhy, Oliver E. Flouty, Zachary D. Rasmussen, Loreen A. Herwaldt, and Jeremy D. Greenlee
Craniectomy is often performed to decrease intracranial pressure following trauma and vascular injuries. The subsequent cranioplasty procedures may be complicated by surgical site infections (SSIs) due to prior trauma, foreign implants, and multiple surgeries through a common incision. Several studies have found that intrawound vancomycin powder (VP) is associated with decreased risk of SSIs after spine operations. However, no previously published study has evaluated the effectiveness of VP in cranioplasty procedures. The purpose of this study was to determine whether intrawound VP is associated with decreased risk of SSIs, to evaluate VP’s safety, and to identify risk factors for SSIs after cranioplasty among patients undergoing first-time cranioplasty.
The authors conducted a retrospective cohort study of adult patients undergoing first-time cranioplasty for indications other than infections from January 1, 2008, to July 31, 2014, at an academic health center. Data on demographics, possible risk factors for SSIs, and treatment with VP were collected from the patients’ electronic health records.
During the study period, 258 patients underwent first-time cranioplasties, and 15 (5.8%) of these patients acquired SSIs. Ninety-two patients (35.7%) received intrawound VP (VP group) and 166 (64.3%) did not (no-VP group). Patients in the VP group and the no-VP group were similar with respect to age, sex, smoking history, body mass index, and SSI rates (VP group 6.5%, no-VP group 5.4%, p = 0.72). Patients in the VP group were less likely than those in the no-VP group to have undergone craniectomy for tumors and were more likely to have an American Society of Anesthesiologists physical status score > 2. Intrawound VP was not associated with other postoperative complications. Risk factors for SSI from the bivariable analyses were diabetes (odds ratio [OR] 3.65, 95% CI 1.07–12.44), multiple craniotomy procedures before the cranioplasty (OR 4.39, 95% CI 1.47–13.18), prior same-side craniotomy (OR 4.73, 95% CI 1.57–14.24), and prosthetic implants (OR 4.51, 95% CI 1.40–14.59). The multivariable analysis identified prior same-side craniotomy (OR 3.37, 95% CI 1.06–10.79) and prosthetic implants (OR 3.93, 95% CI 1.15–13.40) as significant risk factors for SSIs. After adjusting for potential confounders, patients with SSIs were more likely than those without SSIs to be readmitted (OR 7.28, 95% CI 2.07–25.60).
In this study, intrawound VP was not associated with a decreased risk of SSIs or with an increased risk of complications. Prior same-side craniotomy and prosthetic implants were risk factors for SSI after first-time cranioplasty.