Minimizing Surgeon Radiation Exposure During Operative Treatment of Pediatric Supracondylar Humerus Fractures.

BACKGROUND: Orthopaedic surgeons are exposed to high levels of radiation, which may lead to higher rates of cancer among orthopaedic surgeons. There are a series of techniques currently practiced to pin supracondylar humerus fractures including pinning the arm on the C-arm itself, using a plexiglass rectangle or a graphite floating arm board; however, the variation in radiation exposure to the surgeon is unknown. We aimed to determine how the position of the C-arm affects radiation exposure to the surgeon during the treatment of a pediatric supracondylar humerus fracture. MATERIAL AND METHODS: A simulated operating room was created to simulate a closed reduction and percutaneous pinning of a supracondylar humerus fracture. A phantom model was used to simulate the patient's arm. We assessed performing the procedure with the arm on plexiglass, graphite, or on top of the C-arm image receptor. The C-arm was positioned either with the source down and image receptor up (standard position) or with the source up and image receptor down (inverted position). Radiation exposure was recorded from levels corresponding to the surgeon's head, midline, and groin. The estimated effective dose equivalent was calculated to account for the varying radiation sensitivity of different organs. RESULTS: We found the effective dose equivalent, or the overall body damage from radiation, was 5.4 to 7.8% higher than the surgeon when the C-arm was in the inverted position (source up, image receptor down). We did not find any differences in radiation exposure to the surgeon when the arm was supported on plexiglass versus graphite. CONCLUSION: The C-arm positioned in the standard fashion exposes the surgeon to less damaging radiation. Therefore, when the surgeon is standing, we recommend using the C-arm in the standard position. CLINICAL RELEVANCE: Orthopaedic surgeons who stand should use the C-arm in the standard position to pin supracondylar humerus fractures to lower the risk of ionizing radiation exposure.

Use of a high-speed drill in robotics coupled with navigation for pediatric spine surgery.

With the increasing number of surgeries for pediatric spinal deformities, the aim has been to reduce the associated complications, such as those caused by screw malposition. This case series is an intra-operative experience with a new navigated high-speed revolution drill (Mazor Midas, Medtronic, Minneapolis, MN) for pediatric spinal deformity to assess accuracy and workflow. 88 patients, ranging from 2 to 29 years of age, were included who underwent posterior spinal fusion with the navigated high-speed drill. Diagnoses, Cobb angles, imaging, surgical time, complications, and total number of screws placed are described. Screw positioning was evaluated using fluoroscopy, plain radiography, and CT. Mean age was 15.4 years old. Diagnoses included 47 adolescent idiopathic scoliosis, 15 neuromuscular scoliosis, 8 spondylolisthesis, 4 congenital scoliosis, and 14 other. The mean Cobb angulation for scoliosis patients was 64° and the mean number of levels fused was 10. 81 patients had registration via intraoperative 3-D imaging and 7 had pre-operative CT scan to fluoroscopy registration. There were a total of 1559 screws with 925 placed robotically. 927 drill paths were drilled with the Mazor Midas. 926 out of 927 drill paths were accurate. The mean surgical time was 304 min with the mean robotic time being 46 min. This is the first intra-operative report to our knowledge documenting the experience with the Mazor Midas drill in pediatric spinal deformity showing decreased skiving potential, decreased torque when drilling, and lastly increased accuracy. Level of evidence: level III.

Two-Surgeon Multidisciplinary Approach to Pediatric Cervical Spinal Fusion: A Single-Institution Series and Review of the Literature.

BACKGROUND: A collaborative 2-surgeon approach is becoming increasingly popular in surgery but is not widely used for pediatric cervical spine fusions. The goal of this study is to present a large single-institution experience with pediatric cervical spinal fusion using a multidisciplinary 2-surgeon team, including a neurosurgeon and an orthopedic surgeon. This team-based approach has not been previously reported in the pediatric cervical spine literature. METHODS: A single-institution review of pediatric cervical spine instrumentation and fusion performed by a surgical team composed of neurosurgery and orthopedics during 2002-2020 was performed. Demographics, presenting symptoms and indications, surgical characteristics, and outcomes were recorded. Particular focus was given to describe the primary surgical responsibility of the orthopedic surgeon and the neurosurgeon. RESULTS: A total of 112 patients (54% male) with an average age of 12.1 (range 2-26) years met the inclusion criteria. The most common indications for surgery were os odontoideum with instability (n=21) and trauma (n=18). Syndromes were present in 44 (39%) cases. Fifty-five (49%) patients presented with preoperative neurological deficits (26 motor, 12 sensory, and 17 combined deficits). At the time of the last clinical follow-up, 44 (80%) of these patients had stabilization or resolution of their neurological deficit. There was 1 new postoperative neural deficit (1%). The average time between surgery and successful radiologic arthrodesis was 13.2±10.6 mo. A total of 15 (13%) patients experienced complications within 90 days of surgery (2 intraoperative, 6 during admission, and 7 after discharge). CONCLUSIONS: A multidisciplinary 2-surgeon approach to pediatric cervical spine instrumentation and fusion provides a safe treatment option for complex pediatric cervical cases. It is hoped that this study could provide a model for other pediatric spine groups interested in implementing a multi-specialty 2-surgeon team to perform complex pediatric cervical spine fusions. LEVEL OF EVIDENCE: Level IV-case series.

The Influence of Race, Income, and Sex on Treatment and Complications of Common Pediatric Orthopedic Fractures.

Despite best intentions, health care disparities exist and can consequently impact patient care. Few studies have examined the impact of disparities in pediatric orthopedic populations. The current study aimed to determine if the treatment type or complication rates of supracondylar, both-bone forearm, or femur fractures are associated with race, ethnicity, sex, or socioeconomic status. The New York Healthcare Cost and Utilization Project's database was used to identify all pediatric patients treated for supracondylar humerus fractures, both-bone forearm fractures, and femoral shaft fractures in 2016. Risk-adjusted relationships with race, ethnicity, sex, hospital location, and median income by zip code were assessed with multivariable logistic regression. Patients who were non-White, resided in the zip codes with the lowest median income (<$42,999 annually), and were treated in metropolitan areas were more likely to receive nonoperative treatments for supracondylar humerus fractures. Female patients with a femoral shaft fracture were less likely to be treated with open reduction and internal fixation vs intramedullary fixation. Finally, complications were not associated with patient race, sex, or socioeconomic statuses. These findings bring attention to health care disparities in the treatment of common pediatric orthopedic fractures. Further studies investigating the underlying etiology behind these disparities are warranted. [Orthopedics. 2023;46(3):e156-e160.].

Innovative technique for early-onset scoliosis casting using Jackson table.

PURPOSE: Early-onset scoliosis (EOS) can have harmful effects on pulmonary function. Serial elongation, derotation, and flexion (EDF) casting can cure EOS or delay surgical intervention. Most described casting techniques call for specialized tables, which are not available at many institutions. We describe an innovative technique for EDF casting utilizing a modified Jackson table (MJ) and compare results to a Risser frame (RF). METHODS: All patients who underwent EDF casting at our institution between January 2015 and January 2019 were identified and retrospectively reviewed. Patients were stratified by type of table used and clinical and radiographic outcomes were compared. Standard descriptive statistics were calculated. RESULTS: We identified 25 patients who underwent 77 casting events, 11 on an MJ table and 14 on a RF. Mean follow-up was 32 months (range 11-61 months). 28% of patients had idiopathic scoliosis. There was no significant difference in age at initiation of casting (P = 0.3), initial Cobb angle (equivalence, P = 0.009), or rate of idiopathic scoliosis between the MJ and RF groups. There was no significant difference in initial coronal Cobb angle percent correction (equivalence, P = 0.045) or percent correction at 1-year follow-up (equivalence, P = 0.010) between the two groups. There was no difference in cast related complications. There was a significant difference in surgical time, with the MJ group 11 min shorter than the RF (P = 0.005). CONCLUSION: The MJ table is a safe and effective alternative for applying EDF casts under traction without the need for a specialized table. LEVEL OF EVIDENCE: III.

Quality Measures for Pediatric Orthopaedic Surgery: A Systematic Review.

BACKGROUND: Quality measures provide a way to assess health care delivery and to identify areas for improvement that can inform patient care delivery. When operationalized by a hospital or a payer, quality measures can also be tied to physician or hospital reimbursement. Prior work on quality measures in orthopaedic surgery have identified substantial gaps in measurement portfolios and have highlighted areas for future measure development. This study aims to identify the portfolio of quality measures in pediatric orthopaedic surgery. METHODS: We used methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and reviewed PubMed/ MEDLINE and EMBASE, the American Academy of Orthopaedic Surgery (AAOS), National Quality Forum (NQF), and the Agency for Healthcare Research and Quality (AHRQ), for quality measures and candidate quality measures. Quality measure and candidate quality measures were categorized as structure, process, or outcome. Measures were also classified into 1 of the 6 National Quality Strategy priorities (safety, effective, patient centered, timely, efficient, and equitable). RESULTS: A review of PubMed/EMBASE returned 1640 potential quality measures and articles. A review of AAOS, NQF, and AHRQ databases found 80 potential quality measures. After screening we found a total of 18 quality measures and candidate quality measures specifically for pediatric orthopaedic surgery. Quality measures addressed conditions such as supracondylar humerus fractures, developmental dysplasia of the hip, and osteochondritis dissecans. There were 10 process measures, 8 outcome measure, and 0 structure measures. When we categorized by National Quality Strategy priorities and found 50% (9/18) were effective clinical care, 44% (8/18) were person and care-giver centered experience and outcomes, 6% (1/18) were efficient use of resources. CONCLUSIONS: There are few quality measures and candidate quality measures to assess pediatric orthopaedic surgery. Of the quality measure available, process measures are relatively over-represented. Pediatric orthopaedic surgeons can lead the development of outcome (eg, patient-reported outcomes after surgery) and structure measures (eg, subspecialty training certification) to assess quality of care in pediatric orthopaedic surgery. LEVEL OF EVIDENCE: Level II-systematic review.

Double Sublaminal Band Passage Technique for Spinal Deformity Correction.

Sublaminar band fixation is a reliable way to anchor spinal rods to the vertebral column. This technique is especially useful when the anatomy precludes safe pedicle screw placement. Sublaminar bands allow for deformity correction and stabilization of the spine. One of the disadvantages of using the sublaminar band technique is the risk for neurologic injury during the passage of the band between the dura and lamina. In this article, we describe a new technique for passing sublaminar bands, i.e., the double sublaminar band passage technique. This technique decreases the number of passes against the dura, thereby decreasing the opportunity for neural injury. In addition, we present an illustrative case of an 11-year-old female with neuromuscular scoliosis who underwent a posterior spinal instrumented fusion with a hybrid screw and sublaminar band construct.

Indications for and Risks Associated With Implant Removal After Pediatric Trauma.

A wide range of implants are used in the treatment of pediatric fractures, including wires, plates, screws, flexible rods, rigid rods, and external fixation devices. Pediatric bones differ from adult bones both mechanically and biologically, including the potential for remodeling. Implants used in pediatric trauma patients present a unique set of circumstances regarding indications, risks, timing of implant removal, weight-bearing restrictions, and long-term sequelae. Indications for implant removal include wire/pin fixation, when substantial growth remains, and infection. When considering implant removal, the risks and benefits must be assessed. The primary risk of implant removal is refracture. The timing of implant removal varies widely from several weeks to a year or more with the option of retention depending on the fracture, type of implant, and skeletal maturity of the patient.

Test of Strength: Figure-of-Eight versus Spiral Wrapping Technique for Fiberglass Casts.

Pediatric fractures are a common injury, and treatment often includes cast immobilization. For pediatric patients being treated in a cast, cast damage is among the most common reasons patients return to the emergency room. The figure-of-eight wrapping technique interdigitates layers of fiberglass which may create a stronger cast. The aim of this study was to assess the strength of the figure-of-eight wrapping technique in comparison to the spiral wrapping technique. A total of 10 casts were wrapped with a three-inch fiberglass using the spiral technique and 10 casts were wrapped using the figure-of-eight technique. Each cast was then subjected to a three-point bending test and loaded until failure using an Instron machine. The figure-of-eight technique had an average load to failure of 278.2 + 27.6 N/mm which was similar to the spiral technique's load to failure of 281.2 + 25.4 N/mm (p=0.795). Prior to normalizing for thickness, the load to failure of the figure-of-eight technique was 949.8 + 109.5 N, which was significantly higher than the spiral technique of 868.2 + 65.1 N (p=0.038). The figure-of-eight casts were slightly thicker than the spiral casts (average 0.3 mm, p=0.004). This suggests that the thickness of the fiberglass cast may improve the strength. The figure-of-eight wrapping technique had similar biomechanical characteristics to spiral wrapping techniques. Providers should wrap in whichever technique they feel most comfortable performing as there is no difference in strength of the cast. If a stronger cast is desired, then thickness of the cast can be increased.

Does the location of short-arm cast univalve effect pressure of the three-point mould?

PURPOSE: Forearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however, the risk for re-displacement is high (7% to 39%). Proper cast application and the three-point moulding technique are modifiable factors that improve the ability of a cast to maintain the fracture reduction. Many providers univalve the cast to accommodate swelling. This study describes how the location of the univalve cut impacts the pressure at three-point mould sites for a typical dorsally displaced distal radius fracture. METHODS: We placed nine force-sensing resistors on an arm model to collect pressure data at the three-point mould sites. Sensory inputs were sampled at 15 Hz. Cast padding and a three-point moulded short arm fibreglass cast was applied. The cast was then univalved on the dorsal, volar, radial or ulnar aspect. Pressure recordings were obtained throughout the procedure. RESULTS: A total of 24 casts were analyzed. Casts univalved in the sagittal plane (dorsal or volar surface) retained up to 16% more pressure across the three moulding sites compared with casts univalved in the coronal plane (radial or ulnar border). CONCLUSION: Maintaining pressure at the three-point mould prevents loss of reduction at the fracture site. This study shows that univalving the cast dorsally or volarly results in less pressure loss at moulding sites. This should improve the chances of maintaining fracture reductions when compared with radial or ulnar cuts in the cast. Sagittal plane univalving of forearm casts is recommended.

Computer Navigation vs Conventional Total Hip Arthroplasty: A Medicare Database Analysis.

BACKGROUND: Computer-assisted surgery (CAS) is applied to total hip arthroplasty (THA) in an attempt to optimize implant positioning. The effect of CAS on postoperative complications after THA remains unknown. Our study aims to assess the change in complication rates when CAS is used in THA. METHODS: The Medicare database was studied from 2005 to 2012. All THAs performed with CAS were identified. A total of 64,944 THAs were identified, including 5412 CAS-THAs and 59,532 conventional THAs. Medical and surgical adverse events were collected at various time points. RESULTS: CAS-THA was not associated with a decreased rate of dislocation at 30 days (1.0% vs 1.2%; odds ratio [OR], 1.14; P = .310), 90 days (1.1% vs 1.4%; OR, 1.23; P = .090), or 2 years (2.3% vs 2.3%; OR, 1.01; P = .931). CAS-THA was associated with a significantly higher rate of periprosthetic fracture at 30 days (0.4% vs 0.6%; OR, 1.46; P = .040) as well as revision THA at 30 days (1.0% vs 1.4%; OR, 1.43; P = .003) and 90 days (1.2% vs 1.7%; OR, 1.42; P < .002) when compared to conventional THA. CAS-THA was associated with a significantly lower rate of deep vein thrombosis and pulmonary embolism when compared to conventional THA at all time points (P < .05). CONCLUSION: Administrative coding data fail to demonstrate any clinically significant reduction in short-term adverse events with CAS-THA. Further study is warranted to evaluate whether the purported benefits of CAS result in a reduction of the adverse events after THA.

Computer-assisted surgical navigation is associated with an increased risk of neurological complications: a review of 67,264 posterolateral lumbar fusion cases.

BACKGROUND: Pedicle screw malposition may result in neurological complications following posterolateral lumbar fusions (PLF). While computer-assisted navigation (NAV) and intraoperative neuromonitoring (ION) have been shown to improve safety in deformity surgeries, their use in routine PLFs remain controversial. This study assesses the risk of complications and reoperation for pedicle screw revision following PLF with and without ION and/or NAV surgery. METHODS: Retrospective analyses were performed using the Truven Health MarketScan® databases to identify patients that had primary PLF with and without NAV and/or ION for degenerative lumbar disorders from years 2007-2015. Patients undergoing concomitant interbody fusions, spinal deformity surgery or fusion to the thoracic spine were excluded. Complications and reoperation for pedicle screw revision within 90 days of surgery were assessed. RESULTS: During the study period, 67,264 patients underwent PLFs. NAV only was used in 3.5% of patients, ION only in 17.9% and both NAV and ION in 0.8% of patients. In univariate analyses, there was a difference in the risk of neurological injuries among groups (NAV only: 1.4%, ION only: 0.8%, NAV and ION: 0.5%, No NAV or ION: 0.6%, P<0.001). In multivariable models, the use of NAV was associated with a higher risk of neurological complications when compared to ION only or no ION or NAV [NAV vs. ION only: odds ratio (OR) and 95% confidence interval (CI) =2.1 (1.4, 3.2), P=0.002; NAV vs. no ION or NAV: OR and 95% CI =2.5 (1.7, 3.5), P<0.001]. There was no difference in reoperation rates among the groups (P=0.135). CONCLUSIONS: Although the overall risk of neurological complications following PLFs is low, the use of NAV only was associated with an increased risk of neurological complications. No differences were observed in the rates of pedicle screw revision among groups.

Spinal Screening MRI Trends in Patients with Multiple Hereditary Exostoses: National Survey.

Background Multiple hereditary exostoses (MHE) is a rare disease characterized by multiple osteochondromas. Osteochondromas growing into the spinal canal can produce devastating consequences, including permanent neurologic deficits and even death. Routine screening of the entire spinal canal with magnetic resonance imaging (MRI) is a controversial topic lacking a clear consensus or recommendation to guide decision-making. This study presents a case of an intracanal osteochondroma at C1 identified by routine screening and a survey describing current practices of MHE experts. Methods MHE experts were surveyed. Survey questions addressed multiple aspects of care, including the type of practice center, the volume of patients with MHE, and current screening practices. Results A total of 104 experts were contacted, with a total of 26 experts participating in the survey and 23 completing the entire survey. Seventy-two percent of respondents do not perform a routine MRI screen of the spine. For experts that routinely screen, screening is performed across a wide/variable age range (4-18 years). Conclusion Screening protocols for MHE patients to identify osteochondromas within the spinal canal has struggled to reach consensus due to the rarity of the disease. Recent literature provides conflicting advice for patients without neurological symptoms. Our study demonstrates that even experts who are leading the field demonstrate wide practice variability. Most respondents do not routinely perform screening spinal MRI. Due to the wide variability, a national guideline is needed to help guide physician and parental decision-making for patients with MHE. Our case illustrates the potential benefit of identifying an osteochondroma within the spinal canal at a location where further growth could have devastating neurological sequelae.

Corticotropin releasing hormone can selectively stimulate glucose uptake in corticotropinoma via glucose transporter 1.

BACKGROUND: Pre-operative detection of corticotropin (ACTH) secreting microadenomas causing Cushing's disease (CD) improves surgical outcomes. Current best magnetic resonance imaging fails to detect up to 40% of these microadenomas. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is specific, but not sensitive in detecting corticotropinomas. Theoretically, secretagogue stimulation with corticotropin releasing hormone (CRH) could improve detection of adenomas with 18F-FDG PET. Previous attempts with simultaneous CRH stimulation have failed to demonstrate increased 18F-FDG uptake in corticotropinomas. We hypothesized that CRH stimulation leads to a delayed elevation in glucose uptake in corticotropinomas. METHODS: Clinical data was analyzed for efficacy of CRH in improving 18FDG-PET detection of corticotropinomas in CD. Glucose transporter 1 (GLUT1) immunoreactivity was performed on surgical specimens. Ex-vivo, viable cells from these tumors were tested for secretagogue effects (colorimetric glucose uptake), and for fate of intracellular glucose (glycolysis stress analysis). Validation of ex-vivo findings was performed with AtT-20 cells. RESULTS: CRH increased glucose uptake in human-derived corticotroph tumor cells and AtT-20, but not in normal murine or human corticotrophs (p < 0.0001). Continuous and intermittent (1 h) CRH exposure increased glucose uptake in AtT-20 with maximal effect at 4 h (p = 0.001). Similarly, CRH and 8-Br-cAMP led to robust GLUT1 upregulation and increased membrane translocation at 2 h, while fasentin suppressed baseline (p < 0.0001) and CRH-mediated glucose uptake. Expectedly, intra-operatively collected corticotropinomas demonstrated GLUT1 overexpression. Lastly, human derived corticotroph tumor cells demonstrated increased glycolysis and low glucose oxidation. CONCLUSION: Increased and delayed CRH-mediated glucose uptake differentially occurs in adenomatous corticotrophs. Delayed secretagogue-stimulated 18F-FDG PET could improve microadenoma detection.

Functional Outcome After Resection of Von Hippel-Lindau Disease-Associated Cauda Equina Hemangioblastomas: An Observational Cohort Study.

BACKGROUND: Cauda equina hemangioblastomas in von Hippel-Lindau (VHL) disease can cause significant neurological signs and symptoms. Despite their associated morbidity, the management of these tumors remains incompletely defined. OBJECTIVE: To determine optimal management, we analyzed the functional outcomes after resection of these tumors. METHODS: VHL patients who underwent surgical resection of cauda equina hemangioblastomas at the National Institutes of Health and the University of Virginia were included. Clinical and radiological follow-up was performed at 6- to 12-month intervals after surgery. RESULTS: Fifteen patients underwent 18 operations for 21 cauda equina hemangioblastomas (median follow-up 5.9 years). Patients often presented with multiple symptoms, including pain (67%), numbness (50%), urinary complaints (33%), and weakness (11%). Median preoperative tumor volume was 1.2 cm 3 . Four tumors at 3 operations were not resected due to a motor nerve root origin. Gross total resection was achieved in 14 surgeries (93% of operations when resection was attempted). New mild (non-function limiting) neurological symptoms were noted after 11 operations (61%), which most often (64%) resolved within 2 weeks of surgery. At 6-month follow-up, 15 patients (83%) were stable, 2 (11%) were improved, and 1 (6%) was worse. Histological analysis revealed that all tumors originated from within the involved nerve fascicle. CONCLUSIONS: VHL-associated cauda equina hemangioblastomas have an intrafascicular origin and require interruption of the rootlet of origin for complete resection. Motor nerve root involvement may preclude complete resection but strategies including bony decompression and/or interruption of vascular supply may provide a therapeutic option. Nevertheless, most VHL patients with symptom-producing lesions improve with resection.

ZEB1 expression is increased in IDH1-mutant lower-grade gliomas.

Transcription factors that induce epithelial-mesenchymal transition (EMT) promote invasion, chemoresistance and a stem-cell phenotype in epithelial tumors, but their roles in central nervous system tumors are not well-understood. We hypothesized these transcription factors have a functional impact in grades II-III gliomas. Using the National Cancer Institute (NCI) Repository for Molecular Brain Neoplasia Data (REMBRANDT) and the Cancer Genome Atlas (TCGA) Lower-Grade Glioma (LGG) data, we determined the impact of EMT-promoting transcription factors (EMT-TFs) on overall survival in grades II-III gliomas, compared their expression across common genetic subtypes and subsequently validated these findings in a set of 31 tumors using quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Increased expression of the gene coding for the transcriptional repressor Zinc Finger E box-binding Homeobox 1 (ZEB1) was associated with a significant increase in overall survival (OS) on Kaplan-Meier analysis. Genetic subtype analysis revealed that ZEB1 expression was relatively increased in IDH1/2-mutant gliomas, and IDH1/2-mutant gliomas expressed significantly lower levels of many ZEB1 transcriptional targets. Similarly, IDH1/2-mutant tumors expressed significantly higher levels of targets of microRNA 200C (MIR200C), a key regulator of ZEB1. In a validation study, ZEB1 mRNA was significantly increased in IDH1-mutant grades II-III gliomas, and ZEB1 protein expression was more pronounced in these tumors. Our findings demonstrate a novel relationship between IDH1/2 mutations and expression of ZEB1 and its transcriptional targets. Therapy targeting ZEB1-associated pathways may represent a novel therapeutic avenue for this class of tumors.

Endosphenoidal coil for intraoperative magnetic resonance imaging of the pituitary gland during transsphenoidal surgery.

OBJECTIVE Pituitary MR imaging fails to detect over 50% of microadenomas in Cushing's disease and nearly 80% of cases of dural microinvasion. Surface coils can generate exceptionally high-resolution images of the immediately adjacent tissues. To improve imaging of the pituitary gland, a receive-only surface coil that can be placed within the sphenoid sinus (the endosphenoidal coil [ESC]) during transsphenoidal surgery (TSS) was developed and assessed. METHODS Five cadaver heads were used for preclinical testing of the ESC. The ESC (a double-turn, 12-mm-diameter surface coil made from 1-mm-diameter copper wire) was developed to obtain images in a 1.5-T MR scanner. The ESC was placed (via a standard sublabial TSS approach) on the anterior sella face. Clinical MR scans were obtained using the 8-channel head coil and ESC as the receiver coils. Using the ESC, ultra-high-resolution, 3D, balanced fast field echo (BFFE) and T1-weighted imaging were performed at resolutions of 0.25 × 0.25 × 0.50 mm3 and 0.15 × 0.15 × 0.30 mm3, respectively. RESULTS Region-of-interest analysis indicated a 10-fold increase in the signal-to-noise ratio (SNR) of the pituitary when using the ESC compared with the 8-channel head coil. ESC-related improvements (p < 0.01) in the SNR were inversely proportional to the distance from the ESC tip to the anterior pituitary gland surface. High-resolution BFFE MR imaging obtained using ESC revealed a number of anatomical features critical to pituitary surgery that were not visible on 8-channel MR imaging, including the pituitary capsule, the intercavernous sinus, and microcalcifications in the pars intermedia. These ESC imaging findings were confirmed by the pathological correlation with whole-mount pituitary sections. CONCLUSIONS ESC can significantly improve SNR in the sellar region intraoperatively using current 1.5-T MR imaging platforms. Improvement in SNR can provide images of the sella and surrounding structures with unprecedented resolution. Clinical use of this ESC may allow for MR imaging detection of previously occult pituitary adenomas and identify microscopic invasion of the dura or cavernous sinus.

Tumors displaying hybrid schwannoma and neurofibroma features in patients with neurofibromatosis type 2.

Although schwannoma and neurofibroma tumors are generally reported as distinct pathologic diagnoses, sporadic schwannoma/neurofibroma hybrid nerve sheath tumors have been reported in the general population with components of both entities. We report the clinicopathological features of these hybrid nerve sheath tumors in patients with neurofibromatosis type 2 (NF2). A retrospective review of nerve sheath tumor surgical specimens from patients with NF2 enrolled at the National Institutes of Health was performed. Those specimens reported to have schwannoma-like and neurofibromalike features were selected for further characterization by morphology, immunohistochemical panel (CD34, S100, neurofilament triplet protein (immunostain) (NFTP), epithelial membrane antigen (EMA)), and confirmation as hybrid tumors. Of 43 total NF2 patients undergoing resection of nerve sheath tumors, 11 specimens from 11 (26%) patients were found to be benign nerve sheath tumors exhibiting hybrid features of both neurofibroma and schwannoma. Immunohistochemical studies showed the schwannoma component to be S100+, CD 34- while the neurofibroma component was CD34+, variable S100+. Our experience emphasizes the importance of including this distinct tumor subtype, the schwannoma/neurofibroma hybrid tumor, in the differential diagnosis of nerve sheath tumors in NF2 patients and suggests that the relationship between neurofibroma and schwannoma tumors is closer than previously suspected..

Different imaging characteristics of concurrent pituitary adenomas in a patient with Cushing's disease.

We report a patient with Cushing's disease (CD) and two pituitary adenomas that demonstrated different imaging characteristics and therefore suggest an alternative imaging strategy for these patients. A 42-year-old woman presented with signs and symptoms of CD. Biochemical evaluation confirmed hypercortisolemia and suggested CD. On pituitary MRI with spoiled gradient recalled acquisition in the steady-state and T1-weighted spin echo protocols, a 5mm hypoenhancing region typical for a pituitary adenoma was identified on the left. However, after surgical resection the patient remained hypercortisolemic and pathology revealed a non-functional adenoma. At early repeat surgical exploration a 10mm adenoma was found in the right side of the gland. Postoperatively the patient became hypocortisolemic and pathology demonstrated an adrenocorticotropic hormone (ACTH)-staining adenoma. On review of the initial MRI this tumor corresponded to a region of contrast retention best visualized on delayed fluid attenuated inversion recovery (FLAIR) imaging. While the incidentaloma in this case demonstrated classical imaging characteristics of a pituitary adenoma the larger ACTH-secreting tumor was best appreciated by contrast retention. This suggests a role for delayed postcontrast FLAIR imaging in the preoperative evaluation of CD. ACTH-secreting tumors causing CD cause significant morbidity. Due to their small size, a pituitary adenoma is frequently not identified on imaging despite endocrinologic testing suggesting CD. Regardless of improvements in MRI, many tumors are only identified at surgical exploration.

High-resolution(18)F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging for pituitary adenoma detection in Cushing disease.

OBJECT High-resolution PET (hrPET) performed using a high-resolution research tomograph is reported as having a resolution of 2 mm and could be used to detect corticotroph adenomas through uptake of(18)F-fluorodeoxyglucose ((18)F-FDG). To determine the sensitivity of this imaging modality, the authors compared(18)F-FDG hrPET and MRI detection of pituitary adenomas in Cushing disease (CD). METHODS Consecutive patients with CD who underwent preoperative(18)F-FDG hrPET and MRI (spin echo [SE] and spoiled gradient recalled [SPGR] sequences) were prospectively analyzed. Standardized uptake values (SUVs) were calculated from hrPET and were compared with MRI findings. Imaging findings were correlated to operative and histological findings. RESULTS Ten patients (7 females and 3 males) were included (mean age 30.8 ± 19.3 years; range 11-59 years). MRI revealed a pituitary adenoma in 4 patients (40% of patients) on SE and 7 patients (70%) on SPGR sequences.(18)F-FDG hrPET demonstrated increased(18)F-FDG uptake consistent with an adenoma in 4 patients (40%; adenoma size range 3-14 mm). Maximum SUV was significantly higher for(18)F-FDG hrPET-positive tumors (difference = 5.1, 95% CI 2.1-8.1; p = 0.004) than for(18)F-FDG hrPET-negative tumors.(18)F-FDG hrPET positivity was not associated with tumor volume (p = 0.2) or dural invasion (p = 0.5). Midnight and morning ACTH levels were associated with(18)F-FDG hrPET positivity (p = 0.01 and 0.04, respectively) and correlated with the maximum SUV (R = 0.9; p = 0.001) and average SUV (R = 0.8; p = 0.01). All(18)F-FDG hrPET-positive adenomas had a less than a 180% ACTH increase and(18)F-FDG hrPET-negative adenomas had a greater than 180% ACTH increase after CRH stimulation (p = 0.03). Three adenomas were detected on SPGR MRI sequences that were not detected by(18)F-FDG hrPET imaging. Two adenomas not detected on SE (but no adenomas not detected on SPGR) were detected on(18)F-FDG hrPET. CONCLUSIONS While(18)F-FDG hrPET imaging can detect small functioning corticotroph adenomas and is more sensitive than SE MRI, SPGR MRI is more sensitive than(18)F-FDG hrPET and SE MRI in the detection of CD-associated pituitary adenomas. Response to CRH stimulation can predict(18)F-FDG hrPET-positive adenomas in CD.