Rory R. Mayer

Neuronavigation in minimally invasive spine surgery

OBJECT Parallel advancements in image guidance technology and minimal access techniques continue to push the frontiers of minimally invasive spine surgery (MISS). While traditional intraoperative imaging remains widely used, newer platforms, such as 3D-fluoroscopy, cone-beam CT, and intraoperative CT/MRI, have enabled safer, more accurate instrumentation placement with less radiation exposure to the surgeon. The goal of this work is to provide a review of the current uses of advanced image guidance in MISS. METHODS The authors searched PubMed for relevant articles concerning MISS, with particular attention to the use of image-guidance platforms. Pertinent studies published in English were further compiled and characterized into relevant analyses of MISS of the cervical, thoracic, and lumbosacral regions. RESULTS Fifty-two studies were included for review. These describe the use of the iso-C system for 3D navigation during C1-2 transarticular screw placement, the use of endoscopic techniques in the cervical spine, and the role of navigation guidance at the occipital-cervical junction. The authors discuss the evolving literature concerning neuronavigation during pedicle screw placement in the thoracic and lumbar spine in the setting of infection, trauma, and deformity surgery and review the use of image guidance in transsacral approaches. CONCLUSIONS Refinements in image-guidance technologies and minimal access techniques have converged on spinal pathology, affording patients the ability to undergo safe, accurate operations without the associated morbidities of conventional approaches. While percutaneous transpedicular screw placement is among the most common procedures to benefit from navigation, other areas of spine surgery can benefit from advances in neuronavigation and further growth in the field of image-guided MISS is anticipated.

Neuromonitoring for Intramedullary Spinal Cord Tumor Surgery

BACKGROUND Intramedullary spinal cord tumors (IMSCT) account for about 2%-4% of tumors of the central nervous system. Surgical resection continues to be the most effective treatment modality for most intramedullary tumors, with gross total resection leading to preserved neurologic function and improved survival. However, surgical treatment is often difficult and carries significant risk of postoperative neurologic complications. Intraoperative neuromonitoring has been shown to be of clinical importance in the surgical resection of IMSCT. The main monitoring modalities include somatosensory evoked potentials, transcranial motor evoked potentials via limb muscles or spinal epidural space (D-waves), and dorsal column mapping. These monitoring modalities have been shown to inform surgeons intraoperatively and in many cases, have led to alterations in operative decision. METHODS We reviewed the literature on the usefulness of intraoperative neuromonitoring for intramedullary spinal tumor resection and its role in predicting postoperative neurologic deficits. A MEDLINE search was performed (2000-2015) and 13 studies were reviewed. Detailed information and data from the selected articles were assessed and compiled. Data were extracted showing the role of monitoring in outcomes of surgery. CONCLUSIONS By using intraoperative somatosensory evoked potentials, transcranial motor evoked potentials, D-waves, and dorsal column mapping, spinal injury could be prevented in most cases, thereby improving postoperative neurologic functioning and outcome in patients undergoing surgery for IMSCT.

Should Levetiracetam or Phenytoin Be Used for Posttraumatic Seizure Prophylaxis? A Systematic Review of the Literature and Meta-analysis.

BACKGROUND Posttraumatic seizure (PTS) is a significant complication of traumatic brain injury (TBI). OBJECTIVE To perform a systematic review and meta-analysis to compare levetiracetam with phenytoin for seizure prophylaxis in patients diagnosed with severe TBI. METHODS An inclusive search of several electronic databases and bibliographies was conducted to identify scientific studies that compared the effect of levetiracetam and phenytoin on PTS. Independent reviewers obtained data and classified the quality of each article that met inclusion criteria. A random effects meta-analysis was then completed. RESULTS During June and July 2015, a systematic literature search was performed that identified 6097 articles. Of these, 7 met inclusion criteria. A random-effects meta-analysis was performed. A total of 1186 patients were included. The rate of seizure was 35 of 654 (5.4%) in the levetiracetam cohort and 18 of 532 (3.4%) in the phenytoin cohort. Our meta-analysis revealed no change in the rate of early PTS with levetiracetam compared with phenytoin (relative risk, 1.02; 95% confidence interval, 0.53-1.95; P = .96). CONCLUSION The lack of evidence on which antiepileptic drug to use in PTS is surprising given the number of patients prescribed an antiepileptic drug therapy for TBI. On the basis of currently available Level III evidence, patients treated with either levetiracetam or phenytoin have similar incidences of early seizures after TBI. ABBREVIATIONS ADE, adverse drug eventAED, antiepileptic drugCI, confidence intervalOR, odds ratioPTS, posttraumatic seizureTBI, traumatic brain injury.

Eosinophilic granuloma/Langerhans cell histiocytosis: Pediatric neurosurgery update

Case 1 A 23‐month‐old female was admitted to the neurosurgery service with a 3‐month history of a progressively enlarging neck mass. There was associated redness, swelling, and tenderness to palpation, but no neurological deficits on examination. A noncontrast computed tomography (CT) scan of the neck and magnetic resonance imaging (MRI) with contrast showed an osteolytic contrast‐enhancing lesion primarily involving the C2 posterior elements, with a compressive circumferential epidural component extending from C2 to C5 [Figure 1]. A skeletal survey was negative for any other osseous lesions. She underwent C2 to C5 laminectomy with partial resection of the lesion without complication. Pathology was consistent with Langerhans cell (LC) histiocytosis (LCH). She was discharged home several days after her operation and subsequently started outpatient chemotherapy with cytarabine.

Contribution of Lordotic Correction on C5 Palsy Following Cervical Laminectomy and Fusion.

BACKGROUND C5 palsy is a well-reported complication of cervical spine surgery. The implication of sagittal cervical alignment parameters and their changes after surgery on the incidence of C5 palsy remains unclear. OBJECTIVE We review cervical alignment changes in our cases of C5 palsy after cervical laminectomy and fusion. METHODS Cases of C5 palsy were retrospectively compared with a control group. Preoperative and postoperative upright plain film radiographs were analyzed in blinded fashion. RESULTS Spine registry analysis identified 148 patients who underwent cervical laminectomy and fusion by the senior author over 5 years. There were 18 (12%) cases complicated by postoperative C5 palsy. Nine of these 18 patients had prerequisite upright films and were compared with a randomly constructed case control group of 20 patients. There were no statistically significant differences between the 2 groups in age, proportion of males, and preoperative Nurick score. Measures of sagittal alignment did not differ significantly between the 2 groups on preoperative and postoperative imaging. When comparing the amount of alignment change between preoperative and postoperative upright imaging, however, patients with C5 palsy had a statistically higher amount of average C4-C5 Cobb angle change (-2.53 vs 0.78°; P = .01). Logistic regression analysis demonstrated that lordotic change in both C4-C5 and C2-C7 Cobb angles were associated with development of palsy. CONCLUSION Lordotic cervical correction, as measured on upright imaging, was statistically larger in patients who had C5 palsy. The role of deformity correction in C5 palsy deserves further study and may inform intraoperative decision making. ABBREVIATION CLF, cervical laminectomy and fusion.

Three-Dimensional Multidetector CT for Anatomic Evaluation of Orbital Tumors

Intricate resection and complex reconstructive procedures often required for primary and metastatic orbital tumors are facilitated by accurate imaging. A three-dimensional (3D) image can be reconstructed from source axial multidetector computed tomography (MDCT) images to visualize orbital tumors. To assess the utility of 3D images in this setting, the 3D images were reconstructed retrospectively for 20 patients with an orbital tumor and compared to two-dimensional (2D) orthogonal MDCT studies. Both types of images were assessed for their capacity to show the bony orbital walls and foramina, extraocular muscles, and optic nerve in the orbit contralateral to the tumor and, in the affected orbit, the extent of the tumor and its relationship to normal orbital contents and associated bone destruction. 3D imaging is most informative when axial images are acquired at 1.25 mm collimation. The optic nerve, extraocular muscles, and well-circumscribed orbital tumors were well visualized on 3D images. On 3D imaging, tumor-associated destruction of the lateral and superior orbital walls was fairly well demonstrated and that of the inferior and medial walls was not. The 3D images provide the surgeon with a comprehensive view of well-circumscribed orbital tumors and its relationship to extraocular muscles, exiting foramina, and the superior and lateral walls.

Is there a “July effect” in pediatric neurosurgery?

PurposeThe belief that July, when resident physicians’ training year begins, may be associated with increased risk of patient morbidity and mortality is known as the “July effect.” This study aimed to compare complication rates after pediatric neurosurgical procedures in the first versus last academic quarters in two national datasets.MethodsData were extracted from the National Surgical Quality Improvement Program-Pediatrics (NSQIP-P) database for year 2012 for 30-day complication events and the Kids’ Inpatient Database (KID) for year 2012 for in-hospital complication events after pediatric neurosurgical procedures. Descriptive and analytic statistical methods were used to characterize the impact of seasonal variation between the first and last quarters on complications.ResultsThree thousand six hundred twenty-four procedures in the NSQIP-P dataset and 14,855 hospitalizations in KID were included in the study cohort. No significant difference was observed between the first and fourth quarters for these complication events: wound disruption/dehiscence, wound infection, nerve injury, bleeding requiring transfusion, central line-associated BSI, deep venous thrombosis/pulmonary embolism, urinary tract infection, renal failure, re-intubation/pulmonary failure, cardiac arrest, stroke, coma, and death. There was no difference in the average length of stay or average length of surgical time. In the NSQIP-P, the first quarter was associated with a significantly increased incidence of pneumonia and unplanned re-operation; there was a trend towards increased incidence of unplanned re-admission and sepsis. In KID, there was no difference in the rate of pneumonia or sepsis.ConclusionFor the majority of morbidity and mortality events, no significant difference was found in occurrence rates between the first and last quarters.

Acute spinal cord injury associated with multilevel pediatric idiopathic intervertebral disc calcification: case report.

Pediatric idiopathic intervertebral disc calcification (PIIVDC) is a rare condition; most cases are reported to be selflimited with conservative management. In this study, we describe a case of PIIVDC presenting with acute incomplete spinal cord injury with Brown-Séquard-plus syndrome that was treated with surgery and demonstrate the subsequent rehabilitation time course.

Readmission and complications within 30 days after intrathecal baclofen pump placement

To describe 30‐day outcomes after intrathecal baclofen (ITB) pump placement in children and identify risk factors for readmission, reoperation, and perioperative complication using the National Surgical Quality Improvement Program‐Pediatric (NSQIP‐P) database.

Association between 18F-FDG PET/CT and MRI appearance of spinal leptomeningeal disease before and after treatment at a tertiary referral center

Objective Leptomeningeal disease (LMD), the presence of metastasis in the subarachnoid space, has devastating implications if left untreated. The gold standard for LMD diagnosis is cytologic analysis of cerebrospinal fluid (CSF); MRI is also used to evaluate suspected LMD. The purpose of this study was to compare the appearance of LMD in the spinal canal on 18F-FDG PET/CT imaging with the appearance of LMD on MRI and with CSF cytology. Methods In twenty-one patients with cytologically-proven spinal LMD, findings on 18F-FDG PET/CT, MRI, and CSF cytology at diagnosis of LMD and after the initiation of treatment for LMD were retrospectively reviewed. Results At diagnosis of LMD, abnormal 18F-FDG avidity was demonstrated in the spinal canal in six patients, and the anatomic distribution of 18F-FDG activity corresponded to the sites of LMD on MRI. All six of these patients were then treated with intrathecal chemotherapy. Follow-up 18F-FDG PET/CT and MRI were obtained in four of the six cases. In all four cases, normalization of 18F-FDG activity in the spinal canal and reduction of enhancement on MRI corresponded to the cytologic response to treatment, as determined by CSF analysis. Conclusion 18F-FDG avidity in the spinal canal greater than the normal contents of the canal can suggest spinal LMD. This abnormal avidity may be detected before the diagnosis of LMD has been established with MRI or CSF cytology. The spinal canal should be routinely evaluated on 18F-FDG PET/CT in patients with suspected LMD so that appropriate treatment is initiated.