Is Immobilization Technique Associated With Postoperative Pubic Rami Diastasis Following Bladder Exstrophy Closure?

OBJECTIVE

Pelvic osteotomies relieve tension of the bladder and fascial closures during bladder exstrophy repair. Multiple techniques for postoperative immobilization of the pelvis and lower extremities have been described. The primary aim of this study was to assess differences in short and long-term changes in pubic rami diastasis when comparing Bryant traction to spica cast immobilization. Secondary aims included a comparison of length of stay, skin-related complications, and urologic outcomes.

METHODS

We performed a single-institutional retrospective review of bladder exstrophy patients younger than 18 months of age who underwent posterior pelvic osteotomy and bladder exstrophy closure from April 2005 to April 2020. Short-term and long-term pubic rami diastasis were defined as postoperative measurements ≤6 months and ≥12 months, respectively. Secondary outcomes included length of stay, pressure ulcer, skin rash/abrasion, urethrocutaneous fistula, and bladder or fascial dehiscence rates. Multivariable logistic regression assessed for an association between immobilization type and degree of diastasis while controlling for age at the time of diastasis measurement and sex.

RESULTS

Fifteen patients underwent Bryant traction and 36 patients underwent spica cast immobilization. In both the short-term and long-term, there was a greater reduction in pubic diastasis in the spica cast group ( P = 0.002 and P = 0.05, respectively). After adjustments, there were higher odds of having a greater reduction in pubic rami diastasis in both the short-term (odds ratio: 2.71, 95% CI: 1.52-4.86, P = 0.001) and long-term (odds ratio: 2.41, 95% CI: 1.00-5.80, P = 0.05). Length of stay was significantly higher in Bryant's traction group (26 vs 19 d, P < 0.001). Rates of pressure ulcers were higher in the Bryant traction group (26.7% vs 0%, P = 0.005). Rates of skin rash/abrasions, urethrocutaneous fistula, and bladder/fascial dehiscence did not differ.

CONCLUSIONS

Spica cast immobilization is a safe and effective immobilization method. Compared with Bryant traction, spica cast immobilization was associated with a greater reduction in postoperative pubic diastasis both short and long-term, along with a shorter length of hospitalization and reduced rate of pressure ulcers.

LEVEL OF EVIDENCE

Level III-therapeutic study.

Rationale for the Development of a Novel Clinical Grading Scale for Postoperative Facial Nerve Function: Results of a Multidisciplinary International Working Group

OBJECTIVE

The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications.

STUDY DESIGN

Survey.

SETTING

A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery.

RESULTS

House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting.

CONCLUSIONS

Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland.

Five-Fraction Stereotactic Radiation for Head and Neck Paragangliomas

PURPOSE/OBJECTIVE(S)

Paragangliomas of the head and neck (HN) are benign, slow-growing neoplasms that are rarely functional. Treatment is often indicated for patients presenting with mass effect, cranial neuropathies, or pulsatile tinnitus. Radiotherapy, traditionally conventionally fractionated, is often used for primary, post-operative, and salvage therapy, given its excellent control rates and reduced risks to adjacent neurovascular structures. Stereotactic ablative radiation (SAbR) offers shorter treatment time, and modern techniques eliminate margins to improve organ-at-risk avoidance. SAbR may offer additional radiobiological sparing of normal structures over single-fraction SAbR. We aimed to evaluate tumor and symptom response, acute and late toxicity rates, and recurrence patterns in HN paraganglioma patients treated with 25 Gy in 5 fractions.

MATERIALS/METHODS

Retrospective chart review collected baseline patient and tumor information, treatment and dosimetry details, acute and long-term toxicity grades (per the CTCAE v. 5.0), symptom and tumor response, and survival. Local control was defined as the absence of local enlargement (per RECIST v. 1.1) or marginal failure and was estimated using the Kaplan-Meier method.

RESULTS

Between December 2009-March 2020, 39 patients received 25 Gy in 5 fractions to 43 HN paragangliomas, of which 17 were treated in 11 patients with hereditary paraganglioma-pheochromocytoma syndrome. Fifteen targets were post-operative recurrent or residual tumors. There were 27 jugulotympanic tumors, 4 jugular, 1 tympanic, 8 vagal, 5 carotid body, and 2 jugulotympanic or vagal. Median follow-up time was 3.3 years (range 0-11.4 years), and 21 targets had at least 4 years of follow-up. Tumor volume decreased by a median of 37%. Three-year local control was 100%. One patient, known to harbor an SDHD mutation, had 2 out-of-field recurrences within the post-operative bed at 7.1 years. Two patients experienced 2 marginal recurrences within the post-operative bed at 6.1 and 8.4 years: one had an SDHB mutation and developed metastatic disease, and the other did not have genetic testing. The most common grade 1-2 acute toxicities were headache and fatigue; the most common grade 1-2 late toxicities were dysphagia and otalgia. There were no grade >2 acute toxicities. A late grade 3 aspiration event was seen in 1 patient who presented with paralyzed vocal cord requiring multiple medialization laryngoplasties. Within 6 months of SAbR, 18% of symptoms or toxicities improved or resolved; 34% improved or resolved more than 6 months after SAbR.

CONCLUSION

This is the largest series of HN paragangliomas treated with SAbR, detailing a 10-year experience with a 5-fraction regimen that is well-tolerated and achieves excellent local control. Post-SAbR recurrences occurred outside of the radiation field but within the post-operative bed, suggesting that some post-operative patients may benefit from expanded radiation volumes or close surveillance for salvage therapy.

Management of Complications in Vestibular Schwannoma Surgery

Microsurgical removal of acoustic neuroma has advanced tremendously; however, complications still occur. Facial nerve injury is the most common detrimental complication and should take precedence over gross tumor removal in cases where there is an unfavorable tumor-facial nerve interface. Cerebrospinal fluid leakage can occur even with meticulous closure techniques and is generally treatable with either lumbar-subarachnoid drainage or revision wound closure. Meningitis is a serious complication that requires a high index of suspicion in the postoperative period. Other less common complications include intraoperative and postoperative vascular injuries. Early identification and treatment can prevent devastating outcomes.

FtsH4 protease controls biogenesis of the PSII complex by dual regulation of high light-inducible proteins

FtsH proteases are membrane-embedded proteolytic complexes important for protein quality control and regulation of various physiological processes in bacteria, mitochondria, and chloroplasts. Like most cyanobacteria, the model species Synechocystis sp. PCC 6803 contains four FtsH homologs, FtsH1-FtsH4. FtsH1-FtsH3 form two hetero-oligomeric complexes, FtsH1/3 and FtsH2/3, which play a pivotal role in acclimation to nutrient deficiency and photosystem II quality control, respectively. FtsH4 differs from the other three homologs by the formation of a homo-oligomeric complex, and together with Arabidopsis thaliana AtFtsH7/9 orthologs, it has been assigned to another phylogenetic group of unknown function. Our results exclude the possibility that Synechocystis FtsH4 structurally or functionally substitutes for the missing or non-functional FtsH2 subunit in the FtsH2/3 complex. Instead, we demonstrate that FtsH4 is involved in the biogenesis of photosystem II by dual regulation of high light-inducible proteins (Hlips). FtsH4 positively regulates expression of Hlips shortly after high light exposure but is also responsible for Hlip removal under conditions when their elevated levels are no longer needed. We provide experimental support for Hlips as proteolytic substrates of FtsH4. Fluorescent labeling of FtsH4 enabled us to assess its localization using advanced microscopic techniques. Results show that FtsH4 complexes are concentrated in well-defined membrane regions at the inner and outer periphery of the thylakoid system. Based on the identification of proteins that co-purified with the tagged FtsH4, we speculate that FtsH4 concentrates in special compartments in which the biogenesis of photosynthetic complexes takes place.

Preoperative Risk Factors for Subsequent Ipsilateral ACL Revision Surgery After an ACL Restoration Procedure

BACKGROUND

Anterior cruciate ligament (ACL) revision surgery is challenging for both patients and surgeons. Understanding the risk factors for failure after bridge-enhanced ACL restoration (BEAR) may help with patient selection for ACL restoration versus ACL reconstruction.

PURPOSE

To identify the preoperative risk factors for ACL revision surgery within the first 2 years after BEAR.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data from the prospective BEAR I, II, and III trials were used to determine the preoperative risk factors for ACL revision surgery. All patients with a complete ACL tear (aged 13-47 years, depending on the trial), who met all other inclusion/exclusion criteria and underwent a primary BEAR procedure within 30 to 50 days from the injury (dependent on the trial), were included. Demographic data (age, sex, body mass index), baseline patient-reported outcomes (International Knee Documentation Committee [IKDC] subjective score, Marx activity score), preoperative imaging results (ACL stump length, notch size, tibial slope), and intraoperative findings (knee hyperextension, meniscal status) were evaluated to determine their contribution to the risk of ipsilateral ACL revision surgery.

RESULTS

A total of 123 patients, with a median age of 17.6 years (interquartile range, 16-23 years), including 67 (54%) female patients, met study criteria. Overall, 18 (15%) patients required ACL revision surgery in the first 2 years after the BEAR procedure. On bivariate analyses, younger age (P = .011), having a contact injury at the time of the initial tear (P = .048), and increased medial tibial slope (MTS; P = .029) were associated with a higher risk of ipsilateral revision surgery. Multivariable logistic regression analyses identified 2 independent predictors of revision: patient age and MTS. The odds of ipsilateral revision surgery were decreased by 32% for each 1-year increase in age (odds ratio, 0.684 [95% CI, 0.517-0.905]; P = .008) and increased by 28% for each 1° increase in MTS (odds ratio, 1.280 [95% CI, 1.024-1.601]; P = .030). Sex, baseline IKDC or Marx score, knee hyperextension, and meniscal status were not significant predictors of revision.

CONCLUSION

Younger age and higher MTS were predictors of ipsilateral ACL revision surgery after the BEAR procedure. Younger patients with higher tibial slopes should be aware of the increased risk for revision surgery when deciding to undergo ACL restoration.

Women’s experiences of accessing vaccines during pregnancy and for their babies during COVID-19

Background

COVID-19 changed access to healthcare, including vaccinations, in the United Kingdom (UK). This study explored UK women’s experiences of accessing pertussis vaccination during pregnancy and infant vaccinations during COVID-19.

Methods

An online cross-sectional survey was completed, between 3rd August-11th October 2020, by 1404 women aged 16+ years who were pregnant at some point after the first UK lockdown from March 23rd 2020. Ten follow-up semi-structured interviews were conducted.

Results

Most women surveyed were pregnant (65.7%) and a third postnatal (34.3%). Almost all women (95.6%) were aware that pertussis vaccination is recommended in pregnancy. Most pregnant (72.1%) and postnatal women (84.0%) had received pertussis vaccination however, access issues were reported. Over a third (39.6%) of women had a pregnancy vaccination appointment changed. COVID-19 made it physically difficult to access pregnancy vaccinations for one fifth (21.5%) of women and physically difficult to access infant vaccinations for almost half of women (45.8%). Nearly half of women (45.2%) reported feeling less safe attending pregnancy vaccinations and over three quarters (76.3%) less safe attending infant vaccinations due to COVID-19. The majority (94.2%) felt it was important to get their baby vaccinated during COVID-19. Pregnant women from ethnic-minorities and lower-income households were less likely to have been vaccinated. Minority-ethnicity women were more likely to report access problems and feeling less safe attending vaccinations for both themselves and their babies. Qualitative analysis found women experienced difficulties accessing antenatal care and relied on knowledge from previous pregnancies to access vaccine appointments.

Conclusions

COVID-19 disrupted access to vaccinations in the UK. Vaccine services must ensure equitable access to vaccine appointments during ongoing and future pandemics including tailoring services for lower income and ethnic minority families.

Key messages

• Pregnancy and infant vaccines was disrupted by COVID-19 with women feeling less safe and having difficulties accessing vaccinations with ethnic minority women more likely to report access issues.

• Equitable access to routine pregnancy and infant vaccine appointments must be prioritised during future pandemics, including considering tailoring services for different population groups.

Changes in the Cross-Sectional Profile of Treated Anterior Cruciate Ligament Within 2 Years After Surgery

Background:

The cross-sectional area (CSA) of the anterior cruciate ligament (ACL) and reconstructed graft has direct implications on its strength and knee function. Little is known regarding how the CSA changes along the ligament length and how those changes vary between treated and native ligaments over time.

Hypothesis:

It was hypothesized that (1) the CSA of reconstructed ACLs and restored ACLs via bridge-enhanced ACL restoration (BEAR) is heterogeneous along the length. (2) Differences in CSA between treated and native ACLs decrease over time. (3) CSA of the surgically treated ACLs is correlated significantly with body size (ie, height, weight, body mass index) and knee size (ie, bicondylar and notch width).

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Magnetic resonance imaging scans of treated and contralateral knees of 98 patients (n = 33 ACL reconstruction, 65 BEAR) at 6, 12, and 24 months post-operation were used to measure the ligament CSA at 1% increments along the ACL length (tibial insertion, 0%; femoral insertion, 100%). Statistical parametric mapping was used to evaluate the differences in CSA between 6 and 24 months. Correlations between body and knee size and treated ligament CSA along its length were also assessed.

Results:

Hamstring autografts had larger CSAs than native ACLs at all time points (P < .001), with region of difference decreasing from proximal 95% of length (6 months) to proximal 77% of length (24 months). Restored ACLs had larger CSAs than native ACLs at 6 and 12 months, with larger than native CSA only along a small midsubstance region at 24 months (P < .001). Graft CSA was correlated significantly with weight (6 and 12 months), bicondylar width (all time points), and notch width (24 months). Restored ACL CSA was significantly correlated with bicondylar width (6 months) and notch width (6 and 12 months).

Conclusion:

Surgically treated ACLs remodel continuously within the first 2 years after surgery, leading to ligaments/grafts with heterogeneous CSAs along the length, similar to the native ACL. While reconstructed ACLs remained significantly larger, the restored ACL had a CSA profile comparable with that of the contralateral native ACL. In addition to size and morphology differences, there were fundamental differences in factors contributing to CSA profile between the ACL reconstruction and BEAR procedures.

Registration:

NCT 02664545 (ClinicalTrials.gov identifier).

Establishment of patient-derived organoid models of lower-grade glioma

BACKGROUND

Historically, creating patient-derived models of lower-grade glioma (LGG) has been challenging, contributing to few experimental platforms that support laboratory-based investigations of this disease. Although organoid modeling approaches have recently been employed to create in vitro models of high-grade glioma (HGG), it is unknown whether this approach can be successfully applied to LGG.

METHODS

In this study, we developed an optimized protocol for the establishment of organoids from LGG primary tissue samples by utilizing physiologic (5%) oxygenation conditions and employed it to produce the first known suite of these models. To assess their fidelity, we surveyed key biological features of patient-derived organoids using metabolic, genomic, histologic, and lineage marker gene expression assays.

RESULTS

Organoid models were created with a success rate of 91% (n = 20/22) from primary tumor samples across glioma histological subtypes and tumor grades (WHO Grades 1-4), and a success rate of 87% (13/15) for WHO Grade 1-3 tumors. Patient-derived organoids recapitulated stemness, proliferative, and tumor-stromal composition profiles of their respective parental tumor specimens. Cytoarchitectural, mutational, and metabolic traits of parental tumors were also conserved. Importantly, LGG organoids were maintained in vitro for weeks to months and reanimated after biobanking without loss of integrity.

CONCLUSIONS

We report an efficient method for producing faithful in vitro models of LGG. New experimental platforms generated through this approach are well positioned to support preclinical studies of this disease, particularly those related to tumor immunology, tumor-stroma interactions, identification of novel drug targets, and personalized assessments of treatment response profiles.

Psychological Readiness to Return to Sport at 6 Months Is Higher After Bridge-Enhanced ACL Restoration Than Autograft ACL Reconstruction: Results of a Prospective Randomized Clinical Trial

Background:

Previous clinical studies have shown that psychological factors have significant effects on an athlete’s readiness to return to sport after anterior cruciate ligament (ACL) reconstruction (ACLR).

Hypothesis:

We hypothesized that patients who underwent bridge-enhanced ACL restoration (BEAR) would have higher levels of psychological readiness to return to sport compared with patients who underwent ACLR.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 100 patients (median age, 17 years; median preoperative Marx activity score, 16) with complete midsubstance ACL injuries were randomized to either the BEAR procedure (n = 65) or autograft ACLR (n = 35 [33 hamstring and 2 bone--patellar tendon—bone]) and underwent surgery within 45 days of injury. Objective, functional, and patient-reported outcomes, including the ACL--Return to Sport after Injury (ACL-RSI) scale, were assessed at 6, 12, and 24 months postoperatively.

Results:

Patients who underwent the BEAR procedure had significantly higher ACL-RSI scores at 6 months compared with those who underwent ACLR (71.1 vs 58.2; P = .008); scores were similar at 12 and 24 months. Baseline factors independently predictive of higher ACL-RSI scores at 6 months were having a BEAR procedure and participating in level 1 sports prior to injury, explaining 15% of the variability in the scores. Regression analysis of baseline and 6-month outcomes as predictors indicated that the International Knee Documentation Committee (IKDC) score at 6 months explained 45% of the 6-month ACL-RSI variance. Subsequent analysis with IKDC excluded from the model indicated that decreased pain, increased hamstring and quadriceps strength in the surgical limb, and decreased side-to-side difference in anteroposterior knee laxity were significant predictors of a higher ACL-RSI score at 6 months, explaining 34% of the variability in scores. Higher ACL-RSI score at 6 months was associated with earlier clearance to return to sports.

Conclusion:

Patients who underwent the BEAR procedure had higher ACL-RSI scores at 6 months postoperatively. Better ACL-RSI scores at 6 months were related most strongly to higher IKDC scores at 6 months and were also associated with lower pain levels, better muscle recovery, and less knee laxity at 6 months.

Registration:

NCT02664545 (ClinicalTrials.gov identifier).

Regional Differences in Anterior Cruciate Ligament Signal Intensity After Surgical Treatment

BACKGROUND

Magnetic resonance-based measurements of signal intensity have been used to track healing of surgically treated anterior cruciate ligaments (ACLs). However, it is unknown how the signal intensity values in different regions of the ligament or graft change during healing.

HYPOTHESES

(1) Normalized signal intensity of the healing graft or repaired ACL is heterogeneous; (2) temporal changes in normalized signal intensity values differ among the tibial, middle, and femoral regions; and (3) there are no differences in regional normalized signal intensity values 2 years postoperatively among grafts, repaired ACLs, and contralateral native ACLs.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Magnetic resonance imaging scans were analyzed from patients in a trial comparing ACL reconstruction (n = 35) with bridge-enhanced ACL repair (n = 65). The ACLs were segmented from images acquired at 6, 12, and 24 months postoperatively and were partitioned into 3 sections along the longitudinal axis (femoral, middle, and tibial). Linear mixed modeling was used to compare location-specific differences in normalized ligament signal intensity among time points (6, 12, and 24 months) and groups (ACL reconstruction, repair, and contralateral native ACL).

RESULTS

For grafts, the middle region had a higher mean normalized signal intensity when compared with the femoral region at all time points (P < .01) but compared with the tibial region only at 6 months (P < .01). For repaired ACLs, the middle region had a higher mean normalized signal intensity versus the femoral region at all time points (P < .01) but versus the tibial region only at 6 and 12 months (P < .04). From 6 to 24 months, the grafts showed the greatest reduction in normalized signal intensity in the femoral and middle regions (vs tibial regions; P < .01), while there were no regional differences in repaired ACLs. At 2 years after surgery, repaired ACLs had a lower normalized signal intensity in the tibial region as compared with reconstructed grafts and contralateral native ACLs (P < .01).

CONCLUSION

The results suggest that graft remodeling is location specific. Repaired ACLs were more homogeneous, with lower or comparable normalized signal intensity values at 2 years as compared with the contralateral native ACL and reconstructed grafts.

Impact of hydraulic retention time on phosphorus removal from wastewater using reactive media

Phosphorus (P) discharge from wastewater treatment plants into the environment contributes to eutrophication issues. Reactive media filters represent an effective, simple and cost-effective solution to decrease the P content. Previous research used various experimental designs and often synthetic wastewater, making assessment of real-world performance difficult. This study assesses the impact of the hydraulic retention time (HRT) on P removal using real wastewater to refine design criteria for full-scale installations. Four media were compared in column experiments for >200 days. Different HRTs were applied and initially the media achieved low P effluent concentrations of >0.1 mg/L PO₄-P, increasing over time. Best P removal was observed for the highest HRT with on average >99%. HRT was seen to be the driving factor for P removal rather than media capacity. Three of the four materials showed pH levels above 12 initially, decreasing over time. Water quality parameters, including organics, solids and metals, were monitored. In-depth analysis confirmed formation of calcium phosphate precipitation on the media's surface. The results suggest the importance of an optimal HRT to achieve high P removal and show that the reactive media application is an appropriate technology for P removal on small sites if the elevated pH is addressed.

Vestibular Schwannoma Tumor Size and Growth Rate Predict Response with Gamma Knife Stereotactic Radiosurgery

Objective The aim of this study is to determine if pretreatment growth of sporadic vestibular schwannomas (VS) predicts postradiosurgery response.

Methods This study was a retrospective chart review at a tertiary referral center of patients with VS that had at least two pretreatment magnetic resonance imaging (MRI) studies at least 6 months apart and underwent Gamma Knife radiosurgery with a minimum of 14 months postradiosurgery imaging surveillance. Tumor linear measurements and volumetric segmentation were assessed before and after radiosurgery. The main outcome measure was persistent enlargement following radiosurgery, defined as 2 mm enlargement in greatest axial diameter or 20% enlargement in volume without size regression.

Results Thirty-five patients met the inclusion criteria. Patients were observed for median pre- and posttreatment intervals of 29.5 and 40.6 months, respectively. Median dose to the tumor margin was 13 Gy. Postradiosurgery enlargement occurred in six (17.1%) and nine (25.7%) patients based on linear and volumetric enlargement definitions, respectively. Pseudoprogression—defined as tumor enlargement—followed by linear or volumetric regression that occurred in 34.3% of tumors, reaching a maximum size at a median time of 6.3 months (3.3–8.4) postradiosurgery. When controlling for age, gender, and radiation dose, preradiosurgery tumor volume less than 0.3 cm3 (odds ratio [OR]: 59.7, p = 0.012) and preradiosurgery tumor diameter growth rate greater than or equal to 2.5 mm/year (OR: 19.3, p = 0.045) were associated with persistent postradiosurgery tumor enlargement.

Conclusion Smaller pretreatment tumor volume and greater linear tumor growth rates were associated with postradiosurgery tumor enlargement when controlling for age, gender, and radiation dose.

Level of Evidence :This study indicates that the level of evidence is V.

Higher Physiologic Platelet Counts in Whole Blood Are Not Associated With Improved ACL Cross-sectional Area or Signal Intensity 6 Months After Bridge-Enhanced ACL Repair

Background:

A bridge-enhanced anterior cruciate ligament (ACL) repair (BEAR) procedure places an extracellular matrix implant, combined with autologous whole blood, in the gap between the torn ends of the ligament at the time of suture repair to stimulate healing. Prior studies have suggested that white blood cell (WBC) and platelet concentrations significantly affect the healing of other musculoskeletal tissues.

Purpose/Hypothesis:

The purpose of this study was to determine whether concentrations of various blood cell types placed into a bridging extracellular matrix implant at the time of ACL repair would have a significant effect on the healing ligament cross-sectional area or tissue organization (as measured by signal intensity). We hypothesized that patients with higher physiologic platelet and lower WBC counts would have improved healing of the ACL on magnetic resonance imaging (MRI) (higher cross-sectional area and/or lower signal intensity) 6 months after surgery.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 61 patients underwent MRI at 6 months after bridge-enhanced ACL repair as part of the BEAR II trial. The normalized signal intensity and average cross-sectional area of the healing ligament were measured from a magnetic resonance stack obtained using a gradient echo sequence. The results were stratified by sex, and univariate and multivariate regression analyses determined significant correlations between blood cell concentrations on these 2 magnetic resonance parameters.

Results:

In unadjusted analyses, older age and male sex were associated with greater healing ligament cross-sectional area (P < .04) but not signal intensity (P > .15). Adjusted multivariable analyses indicated that in female patients, a higher monocyte concentration correlated with a higher ACL cross-sectional area (β = 1.01; P = .049). All other factors measured, including the physiologic concentration of platelets, neutrophils, lymphocytes, basophils, and immunoglobulin against bovine gelatin, were not significantly associated with either magnetic resonance parameter in either sex (P > .05 for all).

Conclusion:

Although older age, male sex, and monocyte concentration in female patients were associated with greater healing ligament cross-sectional area, signal intensity of the healing ligament was independent of these factors. Physiologic platelet concentration did not have any significant effect on cross-sectional area or signal intensity of the healing ACL at 6 months after bridge-enhanced ACL repair in this cohort. Given these findings, factors other than the physiologic platelet concentration and total WBC concentration may be more important in the rate and amount of ACL healing after bridge-enhanced ACL repair.

Females Have Earlier Muscle Strength and Functional Recovery After Bridge-Enhanced Anterior Cruciate Ligament Repair

Background: While a sex effect on outcomes following anterior cruciate ligament (ACL) reconstruction surgery has been previously documented, less is known following bridge-enhanced ACL repair (BEAR). We hypothesized that female sex would have significantly worse early functional outcomes and higher retear rates following primary repair of the ACL enhanced with a tissue-engineered scaffold. Methods: Sixty-five patients (28 males and 37 females), age 14-35 with a complete ACL tear underwent primary repair of the ACL enhanced with a tissue-engineered scaffold (bridge-enhanced ACL repair) within 45 days of injury. International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome (KOOS) scores, as well as instrumented anteroposterior (AP) laxity through KT-1000 testing and functional outcome measures were obtained at time points up to 2 years postoperatively and compared between males and females using mixed model repeated measures analyses and chi square tests. Results: There was no significant sex difference on the postoperative IKDC Subjective Score at 3, 6, 12, or 24 months or any of the five KOOS scores at 12 and 24 months. Instrumented AP laxity testing demonstrated mean (standard deviation) side-to-side differences that were similar in the two sexes at 2 years; 1.7 (2.7) mm and 1.5 (3.7) mm in females and males, respectively, p = 0.72. At 6 months postoperatively, males had a larger deficit in hamstring strength on the operated leg (14.0% vs. 1.7%; p = 0.03) and a larger deficit in quadriceps strength on the operated leg (11.3% vs. 2.0%; p = 0.004); however, no sex difference was noted at 12 or 24 months. Females demonstrated superior single leg hop testing at 6 and 12 months ([91.3% vs. 78.1%, p = 0.001], [96.9% vs. 87.0%, p = 0.01] respectively). There were no significant sex differences on ipsilateral (males; 14.3% vs. females; 13.9%, p = 1.00) or contralateral (males; 3.6% vs. females; 2.8%, p = 1.00) ACL reinjury rates. Conclusions: Female subjects had better hamstring and quadriceps strength indices at 6 months than males as well as better hop test results at the 6 and 12-month time period. Despite this, there was no significant sex difference on patient-reported outcomes and objective AP laxity testing at time points up to 2 years postoperatively. Impact statement This is the first study comparing sex specific outcomes following the bridge-enhanced ACL repair technique (BEAR). The results of this study suggest that females have earlier recovery of both muscle strength and functional outcomes compared to their male counterparts. This is an important finding when considering future modifications to postoperative care and rehabilitation in females and males following this tissue-engineered BEAR technique.

Resolution of Pain and Predictors of Postoperative Opioid use after Bridge-Enhanced Anterior Cruciate Ligament Repair and Anterior Cruciate Ligament Reconstruction

Purpose

To compare postoperative pain scores and opioid use between patients undergoing a standard arthroscopic anterior cruciate ligament reconstruction (ACLR) using hamstring autograft with those undergoing a suture repair augmented with an extracellular matrix scaffold (bridge-enhanced ACL repair) performed through an arthrotomy and to determine factors predictive of postoperative opioid use and levels of overprescription.

Methods

A nonrandomized controlled trial was conducted with 20 patients (10 ACLR, 10 bridge-enhanced ACL repair), aged 18 to 35 years. All surgeries were performed by a single surgeon. A pain medication log was provided to patients on discharge. No regional anesthesia was performed. Pain scores via a visual analog pain scale were recorded at each visit. Correlations between preoperative and intraoperative characteristics and postoperative opioid use were determined.

Results

The total morphine-equivalent dose ranged from 30 to 309 mg (4-42 pills oxycodone) for the ACLR group and 75 to 254 mg (10-34 pills oxycodone) for the bridge-enhanced ACL repair group. The average opioid use per day was 35.8 mg for the patients undergoing bridge-enhanced ACL repair and 44.2 mg for patients undergoing ACLR (P = .29). Pain scores at time points up to 2 years postoperatively were not significantly different between the 2 groups. Across both groups, the average oversupply of oxycodone was 46 pills per patient, a greater than 70% unused opiate rate. Preoperative body mass index and preoperative Knee Injury and Osteoarthritis Outcome Scores pain score were predictive of greater postoperative opioid use per day, whereas age, concurrent meniscal repair, and operative time were not.

Conclusions

Total overall opiate intake was not different between the patients undergoing bridge-enhanced ACL repair through an arthrotomy and those undergoing arthroscopic ACLR. Both groups had similar pain scores from 2 weeks to 2 years postoperatively. Greater body mass index and greater preoperative pain (lower Knee Injury and Osteoarthritis Outcome Scores pain score) correlated with greater postoperative opioid use per day. There was an overprescription of opioids across all patients.

Level of Evidence

Level III, case control study (therapeutic).

Bridge-Enhanced Anterior Cruciate Ligament Repair Is Not Inferior to Autograft Anterior Cruciate Ligament Reconstruction at 2 Years: Results of a Prospective Randomized Clinical Trial

BACKGROUND

Preclinical studies suggest that for complete midsubstance anterior cruciate ligament (ACL) injuries, a suture repair of the ACL augmented with a protein implant placed in the gap between the torn ends (bridge-enhanced ACL repair [BEAR]) may be a viable alternative to ACL reconstruction (ACLR).

HYPOTHESIS

We hypothesized that patients treated with BEAR would have a noninferior patient-reported outcomes (International Knee Documentation Committee [IKDC] Subjective Score; prespecified noninferiority margin, -11.5 points) and instrumented anteroposterior (AP) knee laxity (prespecified noninferiority margin, +2-mm side-to-side difference) and superior muscle strength at 2 years after surgery when compared with patients who underwent ACLR with autograft.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

One hundred patients (median age, 17 years; median preoperative Marx activity score, 16) with complete midsubstance ACL injuries were enrolled and underwent surgery within 45 days of injury. Patients were randomly assigned to receive either BEAR (n = 65) or autograft ACLR (n = 35 [33 with quadrupled semitendinosus-gracilis and 2 with bone-patellar tendon-bone]). Outcomes-including the IKDC Subjective Score, the side-to-side difference in instrumented AP knee laxity, and muscle strength-were assessed at 2 years by an independent examiner blinded to the procedure. Patients were unblinded after their 2-year visit.

RESULTS

In total, 96% of the patients returned for 2-year follow-up. Noninferiority criteria were met for both the IKDC Subjective Score (BEAR, 88.9 points; ACLR, 84.8 points; mean difference, 4.1 points [95% CI, -1.5 to 9.7]) and the side-to-side difference in AP knee laxity (BEAR, 1.61 mm; ACLR, 1.77 mm; mean difference, -0.15 mm [95% CI, -1.48 to 1.17]). The BEAR group had a significantly higher mean hamstring muscle strength index than the ACLR group at 2 years (98.2% vs 63.2%; P < .001). In addition, 14% of the BEAR group and 6% of the ACLR group had a reinjury that required a second ipsilateral ACL surgical procedure (P = .32). Furthermore, the 8 patients who converted from BEAR to ACLR in the study period and returned for the 2-year postoperative visit had similar primary outcomes to patients who had a single ipsilateral ACL procedure.

CONCLUSION

BEAR resulted in noninferior patient-reported outcomes and AP knee laxity and superior hamstring muscle strength when compared with autograft ACLR at 2-year follow-up in a young and active cohort. These promising results suggest that longer-term studies of this technique are justified.

REGISTRATION

NCT02664545 (ClinicalTrials.gov identifier).

Analysis of Milk-Based Infant Formula. Phase IV. Iodide, Linoleic Acid, and Vitamins D and K: U.S. Food and Drug Administration-Infant Formula Council: Collaborative Study

In 1982, the U.S. Food and Drug Administration, the Infant Formula Council and its member companies, contract laboratories, and other government laboratories began a study of analytical methods for the nutrients listed in the Infant Formula Act of 1980. Phases I, II, III, and V have been completed. The present report provides data on Phase IV, in which 13 laboratories collaboratively studied an ion-selective electrode method for analyzing iodide, a gas chromatographic method for linoleic acid, and 2 liquid chromatographic (LC) methods each for vitamins D and K. Data were insufficient to evaluate one each of the LC methods studied for vitamins K and D. The relative standard deviations (RSD) are sufficient for the nutrient levels found in infant formula. RSDs (%) for repeatability (RSDr) and reproducibility (RSDR), respectively, were as follows: iodide, 4.0-11.4 and 13.5-18.2; linoleic acid, 1.0-1.6 and 3.5-5.1; vitamin K1, 3.2-16.0 and 6.2-19.4; and vitamin D3,4.2 and 35.0. The recommendation to adopt the method for vitamin D was supported by the results of a ministudy. All laboratories were capable of using these methods with little training. The methods for determination of iodide, linoleic acid, and vitamins D and K in ready-to-feed milkbased infant formula have been adopted first action by AOAC International.

Patient Demographics Influencing Vestibular Schwannoma Size and Initial Management Plans

OBJECTIVE

To explore patient demographics as to predicting vestibular schwannoma (VS) size and treatment plan within a single institution.

METHODS

Using a large tertiary referral skull base center database, all patients with sporadic VS who presented to the center between 2009 and 2018 were reviewed.

RESULTS

A total of 816 patients with VS over 18 years of age were included. The median age was 56.8 years (range: 18.6-90.9 years). The median tumor diameter at diagnosis was 11.9 mm (range: 0.6-51.1 mm). With multivariate analysis, older age was associated with decreased tumor size (0.23 mm, 95% confidence interval [CI]: 0.17-0.29), whereas married patients had larger tumors (2.5 mm, 95% CI: 0.92-4.09). When comparing observation, radiation, or surgery, older patients are more likely to pursue observation as compared with surgery and radiation (odds ratio [OR]: 1.08, 95% CI: 1.06-1.10 and OR: 1.20, 95% CI: 1.08-1.33), respectively. Married patients were less likely to pursue observation as compared with surgery (OR: 0.49, 95% CI: 0.29-0.82). Each additional mile a patient lives farther from the center increases his or her odds of pursuing treatment (OR: 1.002, 95% CI: 1.001-1.003).

CONCLUSIONS

Older age is associated with smaller tumors, whereas married patients have larger tumors at diagnosis as compared with nonmarried patients. Furthermore, married patients are more likely to pursue treatment, specifically surgery, as compared with nonmarried patients, whereas patients who live farther from the center are more likely to pursue treatment.

Considerations of target surface area and the risk of radiosurgical toxicity

OBJECTIVE

The goal of this study was to explore conceptual benefits of characterizing delineated target volumes based on surface area and to utilize the concept for assessing risk of therapeutic toxicity in radiosurgery.

METHODS AND MATERIALS

Four computer-generated targets, a sphere, a cylinder, an ellipsoid and a box, were designed for two distinct scenarios. In the first scenario, all targets had identical volumes, and in the second one, all targets had identical surface areas. High quality stereotactic radiosurgery plans with at least 95% target coverage and selectivity were created for each target in both scenarios. Normal brain volumes V12Gy, V14Gy and V16Gy corresponding to received dose of 12 Gy, 14 Gy and 16 Gy, respectively, were computed and analyzed. Additionally, V12Gy and V14Gy volumes and values for seven prospective toxicity variables were recorded for 100 meningioma patients after Gamma Knife radiosurgery. Multivariable stepwise linear regression and best subset linear regression analyses were performed in two statistical software packages, SAS/STAT and R, respectively.

RESULTS

In a phantom study, for the constant volume targets, the volumes of 12 Gy, 14 Gy and 16 Gy isodose clouds were the lowest for the spherical target as an expected corollary of the isoperimetric inequality. For the constant surface area targets, a conventional wisdom is confirmed, as the target volume increases the corresponding volumes V12Gy, V14Gy and V16Gy also increase. In the 100-meningioma patient cohort, the best univariate model featured tumor surface area as the most significantly associated variable with both V12Gy and V14Gy volumes, corresponding to the adjusted R2 values of 0.82 and 0.77, respectively. Two statistical methods converged to matching multivariable models.

CONCLUSIONS

In a univariate model, target surface area is a better predictor of spilled dose to normal tissue than target largest dimension or target volume itself. In complex multivariate models, target surface area is an independent variable for modeling radiosurgical normal tissue toxicity risk.

RADI-36. FRAME-BASED VERSUS FRAMELESS GAMMA KNIFE RADIOSURGERY FOR BRAIN METASTASES

INTRODUCTION: Brain metastases occur in 10 to 40% of cancer patients. In an effort to avoid the neurocognitive toxicities of whole brain radiation therapy, stereotactic radiosurgery (SRS) has become the preferred treatment option for most brain metastases. Many cancer patients will require several rounds of SRS during the course of their disease. Frame-based radiosurgery causes physical discomfort with each treatment session. We present our experience with frameless Gamma Knife radiosurgery (GKRS) and compare the clinical outcomes to frame-based treatments in the same patient cohort. METHODS: We evaluated all patients with brain metastases who underwent both frame-based and frameless SRS, using the Gamma Knife ICON, between January 2017 and November 2018. 11 patients with 110 unique lesions were included in this analysis. Clinical outcomes, including local control, were compared between the two treatment modalities. RESULTS: Mean patient age was 60.0 (range: 41 – 76) years. Median follow-up was 7.9 (range: 0 – 22.1) months. Median number of metastases treated was 4 (range: 1 – 9) per frame-based treatment and 3 (range: 1 – 10) per frameless treatment. Median number of frame-based and frameless procedures, per patient, was 1 (range: 1 – 3) and 1 (range: 1 – 2), respectively. Median tumor volume was 0.06 (range: 0.01 – 11.49) cm³ in the frame-based treatments and 0.14 (range: 0.01 – 4.22) cm³ in the frameless treatments. Median margin dose was 18 Gy for both the frame-based and frameless treatments. Local control was 86.5 and 91.5% at 6 and 9 months post-treatment, respectively in the frame-based treatments and 82.8 and 87.5% at 6 and 9 months post-treatment, respectively in the frameless treatments. CONCLUSIONS: Frameless GKRS results in similar rates of local control compared to frame-based GKRS. This treatment option should be considered in patients undergoing GKRS, as it balances clinical outcomes with patient comfort.

RADI-33. DISTRIBUTED FRAMELESS GAMMA KNIFE RADIOSURGERY: A NEW TREATMENT PARADIGM FOR PATIENTS WITH BRAIN METASTASES

INTRODUCTION: Stereotactic radiosurgery (SRS) has excellent efficacy for patients with limited intracranial disease. Its use in patients with &gt;10 brain metastases remains controversial. Nonetheless, cancer patients are living longer due to advancements in systemic therapeutics and avoiding the neurocognitive toxicities of whole brain radiation therapy is critical. Recent reports suggest that SRS may be effective in patients with ≥10 metastases. Treating large numbers of brain metastases in a single Gamma Knife radiosurgery (GKRS) treatment session poses several challenges. Treatment of metastases in close proximity to one another leads to an increased dose to normal brain, potentially increasing the risk of necrosis. Furthermore, single session treatment of multiple metastases may last several hours, causing significant patient discomfort. Here, we describe a novel treatment paradigm to address these issues: distributed frameless GKRS. Patients with ≥6 brain metastases undergo multi-session frameless GKRS with both temporal and spatial distribution over 2–5 sessions, decreasing treatment time per day and not treating adjacent metastases simultaneously. METHODS: We evaluated all patients with brain metastases who underwent distributed frameless SRS, using the Gamma Knife ICON, between January 2017 and November 2018. Fifty-one patients with 1097 unique lesions were included in this analysis. RESULTS: Mean patient age was 58.8 (range 29–89) years. Median follow-up was 4.1 (range: 0–20.4) months. The median number of metastases treated was 5 (range: 1–19) per treatment session and 11.5 (range: 3–82) per treatment course. The median number of treatment sessions per treatment course was 3 (range: 2–10). The median number of treatment courses, per patient, was 1 (range: 1–4). The median margin dose was 15 Gy. The median overall survival was 5.9 (range: 0.2–20.9) months. CONCLUSIONS: Distributed frameless Gamma Knife radiosurgery is technically feasible and should be considered in lieu of single session GKRS for patients with ≥6 brain metastases.

Lumbar drain trial outcomes of normal pressure hydrocephalus: a single-center experience of 254 patients

OBJECTIVE

A short-term lumbar drain (LD) trial is commonly used to assess the response of normal pressure hydrocephalus (NPH) patients to CSF diversion. However, it remains unknown whether the predictors of passing an LD trial match the predictors of improvement after ventriculoperitoneal shunting. The aim of this study was to examine outcomes, complication rates, and associations between predictors and outcomes after an LD trial in patients with NPH.

METHODS

The authors retrospectively reviewed the records of 254 patients with probable NPH who underwent an LD trial between March 2008 and September 2017. Multivariate regression models were constructed to examine predictors of passing the LD trial. Complications associated with the LD trial procedure were recorded.

RESULTS

The mean patient age was 77 years and 56.7% were male. The mean durations of gait disturbance, cognitive decline, and urinary incontinence were 29 months, 32 months, and 28 months, respectively. Of the 254 patients, 30% and 16% reported objective and subjective improvement after the LD trial, respectively. Complications included a sheared LD catheter, meningitis, lumbar epidural abscess, CSF leak at insertion site, transient lower extremity numbness, slurred speech, refractory headaches, and hyponatremia. Multivariate analyses using MAX-R revealed that a prior history of stroke predicted worse outcomes, while disproportionate subarachnoid spaces (uneven enlargement of supratentorial spaces) predicted better outcomes after the LD trial (r2 = 0.12, p < 0.05).

CONCLUSIONS

The LD trial is generally safe and well tolerated. The best predictors of passing the LD trial include a negative history of stroke and having disproportionate subarachnoid spaces.

Improved Survival Outcomes for Kidney Cancer Patients With Brain Metastases

BACKGROUND

Brain metastases (BM) occur frequently in patients with metastatic kidney cancer and are a significant source of morbidity and mortality. Although historically associated with a poor prognosis, survival outcomes for patients in the modern era are incompletely characterized. In particular, outcomes after adjusting for systemic therapy administration and International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk factors are not well-known.

PATIENTS AND METHODS

A retrospective database of patients with metastatic renal cell carcinoma (RCC) treated at University of Texas Southwestern Medical Center between 2006 and 2015 was created. Data relevant to their diagnosis, treatment course, and outcomes were systematically collected. Survival was analyzed by the Kaplan-Meier method. Patients with BM were compared with patients without BM after adjusting for the timing of BM diagnosis, either prior to or during first-line systemic therapy. The impact of stratification according to IMDC risk group was assessed.

RESULTS

A total of 56 (28.4%) of 268 patients with metastatic RCC were diagnosed with BM prior to or during first-line systemic therapy. Median overall survival (OS) for systemic therapy-naive patients with BM compared with matched patients without BM was 19.5 versus 28.7 months (P = .0117). When analyzed according to IMDC risk group, the median OS for patients with BM was similar for favorable- and intermediate-risk patients (not reached vs. not reached; and 29.0 vs. 36.7 months; P = .5254), and inferior for poor-risk patients (3.5 vs. 9.4 months; P = .0462). For patients developing BM while on first-line systemic therapy, survival from the time of progression did not significantly differ by presence or absence of BM (11.8 vs. 17.8 months; P = .6658).

CONCLUSIONS

Survival rates for patients with BM are significantly better than historical reports. After adjusting for systemic therapy, the survival rates of patients with BM in favorable- and intermediate-risk groups were remarkably better than expected and not statistically different from patients without BM, though this represents a single institution experience, and numbers are modest.

Hypoglossal schwannomas: A systematic review of the literature

BACKGROUND

Schwannomas of the hypoglossal nerve are rare and account for a very small percentage of non-vestibular schwannomas.

OBJECTIVES

In this systematic review of the literature, we examined the epidemiology, symptomatology, management, and outcomes of patients with hypoglossal schwannomas.

METHODS

The electronic database Pubmed was searched for all reports of hypoglossal schwannomas with descriptions of symptoms, management, and outcome characteristics. Data was extracted from each study and compiled in a spreadsheet. Continuous variables were reported as means and medians. Categorical variables were reported as proportions. Additional analysis was not done due to inconsistent reporting of outcomes and small sample sizes.

RESULTS

A total of 59 studies (94 total individual cases) were included. 64% of patients were female with mean age of 44.6 years. The majority were intracranial/extracranial (50%). The most common symptoms were tongue deviation or speech disturbance (38%) and headaches (33%). Hypoglossal nerve dysfunction was present in 80% of patients. Surgical excision was performed in 93%, with a 15% complication rate. Evidence of residual mass after surgery was noted in 29%. Permanent hypoglossal nerve deficits occurred in 67%. Recurrence of tumor burden was reported in 6 studies, with median time to recurrence of 16.5 months.

CONCLUSION

Current evidence suggests overall favorable outcomes with surgical resection of hypoglossal schwannomas, with a large percentage of patients experiencing mild and usually well-tolerated neurologic deficit. Limitations of this study include the use of retrospective data taken from case reports/series with highly selected patients, selective reporting, and absence of control groups.

Aggressive Behavior in Silent Subtype III Pituitary Adenomas May Depend on Suppression of Local Immune Response: A Whole Transcriptome Analysis

Silent subtype III pituitary adenomas (SS-3) are clinically nonfunctional adenomas that are more aggressive in terms of invasion and risk of recurrence than their conventional null cell counterparts. We previously showed that these tumors can be distinguished by immunohistochemistry based on the identification of a markedly enlarged and fragmented Golgi apparatus. To understand the molecular correlates of differential aggressiveness, we performed whole transcriptome sequencing (RNAseq) on 4 SS-3 and 4 conventional null cell adenomas. The genes that were highly upregulated in all the SS-3 adenomas included 2 secreted proteins involved in the suppression of T-lymphocyte activity, i.e., ARG2 (multiple testing adjusted padj = 1.5 × 10-3) and SEMA3A (padj = 3.3 × 10-3). Highly downregulated genes in all the SS-3 adenomas included HLA-B (padj = 3.3 × 10-6), suggesting reduced antigen presentation by the adenoma to cytotoxic T-cells. Quantitative RT-PCR of these genes performed on the adenoma samples supported the RNAseq results. We also found a relative decrease in the overall concentration of T-lymphocytes in the SS-3 tumors. These results suggest that SS-3 adenomas actively suppress the immune system and raise the possibility that they may be treatable with immune checkpoint inhibitors or nonspecific cancer immunotherapies.

Surgical Outcomes and Postoperative Management in Spontaneous Cerebrospinal Fluid Rhinorrhea

Background  The etiology of spontaneous cerebrospinal fluid (CSF) rhinorrhea remains unknown, though emerging evidence suggests that this likely represents a variant of idiopathic intracranial hypertension. Long-term success rates for repair and postoperative management strategies remain variable. Methods  Retrospective review of patients undergoing surgical management of spontaneous CSF rhinorrhea was conducted over a 5-year period. Analysis was performed to correlate recurrence with demographics and perioperative variables. Lumbar puncture usage and neuro-ophthalmological examinations in clinical management were also assessed. Results  Forty-eight patients were included in the study. The mean age was 51.4 years with 94% females. Leaks were most commonly located in the sphenoid (43.8%) and cribriform region (33.3%). The most common findings on magnetic resonance imaging were empty sella (48%) and Meckel's cave diverticula (24%). Nine patients (18.8%) had recurrent CSF leaks. Six occurred >1 month postoperatively. Three had repeat endoscopic repairs, two received ventriculoperitoneal shunts, and one was managed with a lumbar drain, with overall success rate of 93.8%. Acetazolamide was utilized in 19 cases (39.6%) postoperatively. Overall, 59% of patients had elevated opening pressures on postoperative lumbar puncture ( n  = 32). Neuro-ophthalmology evaluated 28 patients; 25% had visual field deficits, and 7.1% had papilledema. Conclusions  Management of spontaneous CSF leaks remains a significant challenge. Endoscopic repair is successful in most patients with little morbidity; however, postoperative management remains inconsistent, and further studies are warranted to establish consensus on post-surgical care. The association with elevated intracranial pressure and visual field deficits/papilledema suggests opening pressures, and neuro-ophthalmologic evaluation should be considered in the treatment algorithm.

Prospective Longitudinal Analysis of 2-Hydroxyglutarate Magnetic Resonance Spectroscopy Identifies Broad Clinical Utility for the Management of Patients With IDH-Mutant Glioma

Purpose Proton magnetic resonance spectroscopy (MRS) of the brain can detect 2-hydroxyglutarate (2HG), the oncometabolite produced in neoplasms harboring a mutation in the gene coding for isocitrate dehydrogenase ( IDH). We conducted a prospective longitudinal imaging study to determine whether quantitative assessment of 2HG by MRS could serve as a noninvasive clinical imaging biomarker for IDH-mutated gliomas. Patients and Methods 2HG MRS was performed in 136 patients using point-resolved spectroscopy at 3 T in parallel with standard clinical magnetic resonance imaging and assessment. Data were analyzed in patient cohorts representing the major phases of the glioma clinical course and were further subgrouped by histology and treatment type to evaluate 2HG. Histologic correlations were performed. Results Quantitative 2HG MRS was technically and biologically reproducible. 2HG concentration > 1 mM could be reliably detected with high confidence. During the period of indolent disease, 2HG concentration varied by less than ± 1 mM, and it increased sharply with tumor progression. 2HG concentration was positively correlated with tumor cellularity and significantly differed between high- and lower-grade gliomas. In response to cytotoxic therapy, 2HG concentration decreased rapidly in 1p/19q codeleted oligodendrogliomas and with a slower time course in astrocytomas and mixed gliomas. The magnitude and time course of the decrease in 2HG concentration and magnitude of the decrease in tumor volume did not differ between oligodendrogliomas treated with temozolomide or carmustine. Criteria for 2HG MRS were established to make a presumptive molecular diagnosis of an IDH mutation in gliomas technically unable to undergo a surgical procedure. Conclusion 2HG concentration as measured by MRS was reproducible and reliably reflected the disease state. These data provide a basis for incorporating 2HG MRS into clinical management of IDH-mutated gliomas.

Detection of 2-hydroxyglutarate in brain tumors by triple-refocusing MR spectroscopy at 3T in vivo

PURPOSE

To test the efficacy of triple-refocusing MR spectroscopy (MRS) for improved detection of 2-hydroxyglutarate (2HG) in brain tumors at 3T in vivo.

METHODS

The triple-refocusing sequence parameters were tailored at 3T, with density-matrix simulations and phantom validation, for enhancing the 2HG 2.25-ppm signal selectivity with respect to the adjacent resonances of glutamate (Glu), glutamine (Gln), and gamma-aminobutyric acid (GABA). In vivo MRS data were acquired from 15 glioma patients and analyzed with LCModel using calculated basis spectra. Metabolites were quantified with reference to water.

RESULTS

A triple-refocusing sequence (echo time = 137 ms) was obtained for 2HG detection. The 2HG 2.25-ppm signal was large and narrow while the Glu and Gln signals between 2.2 and 2.3 ppm were minimal. The optimized triple refocusing offered improved separation of 2HG from Glu, Gln and GABA when compared with published MRS methods. 2HG was detected in all 15 patients, the estimated 2HG concentrations ranging from 2.4 to 15.0 mM, with Cramer-Rao lower bounds of 2%-11%. The 2HG estimates did not show significant correlation with total choline.

CONCLUSION

The optimized triple refocusing provides excellent 2HG signal discrimination from adjacent resonances and may confer reliable in vivo measurement of 2HG at relatively low concentrations. Magn Reson Med 78:40-48, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Multimodality Management of Trigeminal Schwannomas

Patients presenting with trigeminal schwannomas require multimodality management by a skull base surgical team that can offer expertise in both transcranial and transnasal approaches as well as radiosurgical and microsurgical strategies. Improvement in neurologic symptoms, preservation of cranial nerve function, and control of mass effect are the primary goals of management for trigeminal schwannomas. Complete surgical resection is the treatment of choice but may not be possible in all cases. Radiosurgery is an option as primary management for small- to moderate-sized tumors and can be used for postoperative residuals or recurrences. Planned surgical resection followed by SRS for residual tumor is an effective option for larger trigeminal schwannomas. The endoscopic resection is an excellent approach for patients with an extradural tumor or tumors isolated to the Meckel cave. A detailed analysis of a tumor and its surroundings based on high-quality imaging can help better estimate the expected outcome from each treatment. An expert skull base team should be able to provide precise counseling for each patient's situation for selecting the best option.

Acetate is a bioenergetic substrate for human glioblastoma and brain metastases

Glioblastomas and brain metastases are highly proliferative brain tumors with short survival times. Previously, using (13)C-NMR analysis of brain tumors resected from patients during infusion of (13)C-glucose, we demonstrated that there is robust oxidation of glucose in the citric acid cycle, yet glucose contributes less than 50% of the carbons to the acetyl-CoA pool. Here, we show that primary and metastatic mouse orthotopic brain tumors have the capacity to oxidize [1,2-(13)C]acetate and can do so while simultaneously oxidizing [1,6-(13)C]glucose. The tumors do not oxidize [U-(13)C]glutamine. In vivo oxidation of [1,2-(13)C]acetate was validated in brain tumor patients and was correlated with expression of acetyl-CoA synthetase enzyme 2, ACSS2. Together, the data demonstrate a strikingly common metabolic phenotype in diverse brain tumors that includes the ability to oxidize acetate in the citric acid cycle. This adaptation may be important for meeting the high biosynthetic and bioenergetic demands of malignant growth.