Efficacy and Safety of "Sleeper Plate" in Temporary Hemiepiphysiodesis and the Observation of "Tethering".

BACKGROUND: Guided growth is commonly performed by placing an extraperiosteal 2-hole plate across the growth plate with one epiphyseal and one metaphyseal screw. Recent studies investigated the efficacy of the removal of the metaphyseal screw only (sleeper plate) after correction. They concluded the practice to be unnecessary as only 19% of patients showed recurrence of deformity. This study aims to examine the incidence of rebound and undesired bony in-growth of the plate (tethering) after metaphyseal screw removal only. METHODS: In this retrospective case series, patient data on 144 plates inserted around the knee were obtained. Plates still in situ (n=69) at the time of study and full hardware removal (n=50) were excluded. The remaining 25 plates had only the metaphyseal screw removed after completed deformity correction. We analyzed the rate of tethering, rebound, and maintenance of correction in 2 age groups at latest follow (mean of 3.5 y). The Fisher exact test with Freeman-Halton extension was used to analyze categorical data and the Student t test for descriptive variables. RESULTS: Twenty-five plates were identified as "sleeper plates" in our series. Thirteen plates (52%) maintained the achieved correction after a mean of 21 months (range: 4 to 39 mo), 9 plates (36%) required screw reinsertion due to rebound after a mean of 22 months (range: 12 to 48 mo) from screw removal, and 4 plates (16%) showed tethering with undesired continuation of guided growth after a mean of 14 months (range: 7 to 22 mo) from screw removal. Younger patients (<8 y at time of plate insertion) had higher rates of rebound and tethering ( P =0.0112, Fisher exact test). All tethering occurred in titanium plates, none occurred in steel plates. CONCLUSIONS: The sleeper plate is an acceptable treatment strategy for coronal deformities around the knee, however, tethering and rebound may occur, especially in younger patients. Titanium plates may increase the risk of tethering, however, further long-term follow-up is needed as there were only 6 steel plates versus 19 titanium in this study. We stress the importance of close postoperative follow-up to identify signs of tethering and rebound early to prevent over-correction. LEVEL OF EVIDENCE: Level IV-retrospective case study.

Surgical approaches for resection of third ventricle colloid cysts: meta-analysis.

Although outcome studies and systematic reviews have been published on the surgical treatment of third ventricle colloid cysts (TVCC), there are no meta-analyses that compare the outcomes for various surgical approaches. This meta-analysis assesses the outcomes and complications for transcortical, transcallosal, and endoscopic surgical approaches used to excise TVCCs. A meta-analysis of surgically excised TVCCs was performed with an assessment of outcome for transcortical, transcallosal, and endoscopic approaches. A random-effects model analyzed the extent of surgical excision. The analysis included reports that compared at least two of these surgical approaches, for a total of 11 studies comprising a population of 301 patients. The transcortical approach was associated with a higher incidence of complete excision compared to the endoscopic approach (OR = 0.137, p = 0.041), with no significant differences observed between transcortical and transcallosal approaches, and between transcallosal and endoscopic approaches. Comparison between endoscopic and pooled microsurgical approaches was also insignificant (OR = 0.22, p = 1). The risk of motor weakness was increased with the transcortical approach compared to the endoscopic approach (OR = 6.10, p = 0.018). There were no significant differences between transcortical and transcallosal approaches regarding newly onset seizures, and no significant mortality differences between all three approaches. This study demonstrates that microsurgical approaches are associated with a greater extent of resection compared to endoscopic approaches; however, best results are likely achieved based on the surgeon's expertise, flexibility, and case review.

Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance: case series and systematic review of extent of resection, quantification of postoperative frontal lobe injury, anosmia, and recurrence.

BACKGROUND: Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. OBJECTIVE: To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs. METHODS: We performed a retrospective single-center cohort study and a systematic literature review. RESULTS: Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm3 preoperatively to 9.9 ± 11.4 cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm3; max 7.5 cm3). Median length of stay was 3 days (range 2-8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM. CONCLUSION: The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach. Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

Modernization of bone age assessment: comparing the accuracy and reliability of an artificial intelligence algorithm and shorthand bone age to Greulich and Pyle.

Greulich and Pyle (GP) is one of the most common methods to determine bone age from hand radiographs. In recent years, new methods were developed to increase the efficiency in bone age analysis like the shorthand bone age (SBA) and automated artificial intelligence algorithms. OBJECTIVE: The aim of this study is to evaluate the accuracy and reliability of these two methods and examine if the reduction in analysis time compromises their efficacy. METHODS: Two hundred thirteen males and 213 females had their bone age determined by two separate raters using the SBA and GP methods. Three weeks later, the two raters repeated the analysis of the radiographs. The raters timed themselves using an online stopwatch. De-identified radiographs were securely uploaded to an automated algorithm developed by a group of radiologists in Toronto. The gold standard was determined to be the radiology report attached to each radiograph, written by experienced radiologists using GP. RESULTS: Intraclass correlation between each method and the gold standard fell within the range of 0.8-0.9, highlighting significant agreement. Most of the comparisons showed a statistically significant difference between the new methods and the gold standard; however, it may not be clinically significant as it ranges between 0.25 and 0.5 years. A bone age is considered clinically abnormal if it falls outside 2 standard deviations of the chronological age; standard deviations are calculated and provided in GP atlas. CONCLUSION: The shorthand bone age method and the automated algorithm produced values that are in agreement with the gold standard while reducing analysis time.

The slope of the learning curve in 600 consecutive endoscopic transsphenoidal pituitary surgeries.

BACKGROUND: Endonasal endoscopic transsphenoidal surgery (EETS) for pituitary adenoma has become a mainstay of treatment over the last two decades and it is generally accepted that once this learning curve is achieved, a plateau is reached with little incremental improvement. OBJECTIVE: The objective of this study was to assess the slope of the learning curve over a long period of time for a variety of outcomes measures. METHODS: We examined outcomes and complications in a consecutive series of 600 EETS for pituitary adenoma grouped into quartiles based on date of surgery. RESULTS: GTR significantly increased across quartiles from 55 to 79% in the last quartile (p < 0.005). The rate of intraoperative CSF leak significantly decreased from 60% in the first quartile to 33% in the last quartile and the rate of lumbar drain placement from 28% in the first quartile to 6% in the last quartile (p < 0.005). Hormonal remission for secreting adenomas increased from 68% in the first quartile to 90% in the last quartile (p < 0.05). The rate of post-operative CSF leak trended lower (3% in first quartile to 0.7% in last two quartiles). The greatest improvement in outcome occurred between the first and second quartiles (19.9%), but persistent improvement occurred between the second and third (6.7%) and third and fourth quartiles (8.0%). CONCLUSION: Although the slope of the learning curve is steeper earlier in a surgeon's experience, the slope does not plateau and continues to increase even over more than a decade.

Acellular dermal matrix as an alternative to autologous fascia lata for skull base repair following extended endoscopic endonasal approaches.

BACKGROUND: Skull base reconstruction after extended endoscopic endonasal approaches (EEAs) can be challenging. In addition to the nasoseptal flap, which has been adopted by most centers, autologous fascia lata is also often utilized. Harvesting of fascia lata requires a separate thigh incision, may prolong recovery, and results in a visible scar. In principal, the use of non-autologous materials would be preferable to avoid a second incision and maintain the minimally invasive nature of the approach, assuming the CSF leak rate is not compromised. OBJECTIVE: To assess the efficacy of acellular dermal matrix (ADM) as a non-autologous alternative to autologous fascia lata graft for watertight closure of the cranial base following EEAs. METHODS: A retrospective chart review of extended EEAs performed before and after the transition from fascia lata to ADM was performed. Cases were frequency matched for approach, pathology, BMI, use of lumbar drainage, and tumor volume. Power analysis was performed to estimate the sample size needed to demonstrate non-inferiority. RESULTS: ADM was used for watertight closure of the cranial base in 19 consecutive extended endoscopic endonasal approaches (16 gasket-seals and 3 buttons) with 1 postoperative CSF leak at the last follow-up (median 5.3, range 1.0-12.6 months). All patients had high-flow intraoperative leaks. The cohort included 8 meningiomas, 8 craniopharyngiomas, 2 chordomas, and 1 pituicytoma ranging in size from 0.2 to 37.2cm3 (median 5.5, IQR 2.8-13.3 cm3). In 19 historical controls who received fascia lata, there were 2 postoperative CSF leaks. CONCLUSIONS: Preliminary results suggest that ADM provides a non-inferior non-autologous alternative to fascia lata for watertight gasket-seal and button closures following extended EEAs, potentially reducing or eliminating the need to harvest autologous tissue.

Increased frequency of cataract surgery in patients over age 50 with pituitary macroadenomas and chiasmal compression.

BACKGROUND: Patients with visual loss from macroadenomas compressing their optic apparatus may also have concomitant age-related visual pathology such as cataracts. How these two pathologies interact with each other is not well documented. OBJECTIVE: The interaction between these two pathologies in elderly patients is the subject of this study. METHODS: We identified a series of non-functioning macroadenoma patients over age 50 years with tumors compressing the chiasm who underwent transsphenoidal surgery at our institution between 2004 and 2018. Pre- and post-operative visual complaints, tumor size and extent of resection were analyzed. Prevalence of the diagnosis of cataract and prevalence of cataract surgery in each decade were compared with national averages. RESULTS: We identified 200 patients who met selection criteria. 18% of these patients had a diagnosis of cataract and 12.5% had cataract surgery. Compared with the Eye Diseases Prevalence Research Group (EDPRG) study, the prevalence of cataract surgery was 2.5 times the national average of 5.1%. 32% of these patients had no improvement in their vision after cataract surgery but 76% improved after transsphenoidal surgery. CONCLUSIONS: We reported a high prevalence of cataract surgery in patients over age 50 in patients with pituitary macroadenomas compressing the optic pathway compared with national averages in patients without adenomas. While visual loss from adenoma likely precipitated more cataract surgeries in this group of patients, some who may not have required it, those patients with cataracts who did not have their cataracts extracted were less likely to recover vision after transsphenoidal surgery. Addressing both pathologies is beneficial.

Genomic profile of a primary squamous cell carcinoma arising from malignant transformation of a pineal epidermoid cyst.

Malignant transformation of intracranial epidermoid cysts is a rare occurrence. We present the second case of such an event occurring in the pineal region and the first case sent for detailed genomic profiling. MRI demonstrated two lesions: a cyst in a quadrigeminal cistern with restricted diffusion on DWI-weighted images and an adjacent, peripherally enhancing tumor with cerebellar infiltration. Both the lesions were completely resected with a small residual of the epidermoid cyst. The final pathology of both lesions was consistent with epidermoid cyst and squamous cell carcinoma (SCC), respectively. The tumor specimen was sent for comprehensive genomic profiling which revealed stable microsatellite status and loss of CDKN2A/B, MTAP (exons 2-8), and PTEN (exons 6-9). Although reports of primary SCC originating from the epidermoid cyst have been previously described, this is the first description of the genomic profile of such a tumor.

Endonasal surgery for suprasellar germ cell tumors: two cases and review of the literature.

Germ cell tumors are rare malignant tumors frequently located in the suprasellar region. Definitive treatment is chemotherapy and radiation. However, in some circumstances, surgery is indicated for biopsy or resection. There are limited reports of the role of the endonasal endoscopic approach (EEA) in the management of this tumor. We present two cases in which EEA was utilized for successful management of germ cell tumor. The most challenging aspect of germ cell tumor management for the treating physician is knowing the proper indications for surgery. In this paper, we highlight two specific instances, namely diagnosis and tumor refractory to chemoradiation. Given the suprasellar location, EEA is an ideal approach.

The Great Mimicker: A Unique Case of Diffuse Subarachnoid Haemorrhage Simulating Acute Myocardial Infarction.

Subarachnoid haemorrhage (SAH) is a rare yet consequential medical emergency that may mimic an acute myocardial infarction (MI). SAH causes enhanced sympathetic activity, culminating in the development of neurogenic stunned myocardium (NSM), which presents as ST-segment deviations, prolonged QT intervals, T-wave inversions or Q-waves. Reperfusion therapy is contraindicated for SAH because of an increased risk of bleeding and death. Therefore, a prompt diagnosis is crucial. Here, we report a unique case of massive SAH presenting as diffuse ST-segment deviation simulating an acute MI. Our patient was brought to the emergency department after a cardiac arrest and died on day 2 of admission. LEARNING POINTS: Subarachnoid haemorrhage (SAH) can present with EKG changes and significant rise in troponin, mimicking acute coronary syndrome.SAH should be included in the differential diagnosis for patients presenting with neurological symptoms, ST-segment deviations or prolonged QT intervals.Misdiagnosis of SAH as acute coronary syndrome can lead to inappropriate use of anticoagulants or delays in necessary neurological interventions.

Long-term tumor control after endoscopic endonasal resection of craniopharyngiomas: comparison of gross-total resection versus subtotal resection with radiation therapy.

OBJECTIVE: Surgical management of craniopharyngiomas (CPAs) is challenging. Controversy exists regarding the optimal goals of surgery. The purpose of this study was to compare the long-term outcomes of patients who underwent gross-total resection with the outcomes of those who underwent subtotal resection of their CPA via an endoscopic endonasal approach. METHODS: From a prospectively maintained database of all endoscopic endonasal approaches performed at Weill Cornell Medicine, only patients with CPAs with > 3 years of follow-up after surgery were included. The primary endpoint was radiographic progression. Data were collected on baseline demographics, imaging, endocrine function, visual function, and extent of resection. RESULTS: A total of 44 patients with a mean follow-up of 5.7 ± 2.6 years were included. Of these patients, 14 (31.8%) had prior surgery. GTR was achieved in 77.3% (34/44) of all patients and 89.5% (34/38) of patients in whom it was the goal of surgery. Preoperative tumor volume < 10 cm3 was highly predictive of GTR (p < 0.001). Radiation therapy was administered within the first 3 months after surgery in 1 (2.9%) of 34 patients with GTR and 7 (70%) of 10 patients with STR (p < 0.001). The 5-year recurrence-free/progression-free survival rate was 75.0% after GTR and 25.0% after STR (45% in subgroup with STR plus radiotherapy; p < 0.001). The time to recurrence after GTR was 30.2 months versus 13 months after STR (5.8 months in subgroup with STR plus radiotherapy; p < 0.001). Patients with GTR had a lower rate of visual deterioration and higher rate of return to work or school compared with those with STR (p = 0.02). Patients with GTR compared to STR had a lower rate of CSF leakage (0.0% vs 30%, p = 0.001) but a higher rate of diabetes insipidus (85.3% vs 50%, p = 0.02). CONCLUSIONS: GTR, which is possible to achieve in smaller tumors, resulted in improved tumor control, better visual outcome, and better functional recovery but a higher rate of diabetes insipidus compared with STR, even when the latter was supplemented with postoperative radiation therapy. GTR should be the goal of craniopharyngioma surgery, when achievable with minimal morbidity.

Impact of Medicaid insurance on outcomes following endoscopic transsphenoidal pituitary surgery.

OBJECTIVE: Despite the rise of studies in the neurosurgical literature suggesting that patients with Medicaid insurance have inferior outcomes, there remains a paucity of data on the impact of insurance on outcomes after endonasal endoscopic transsphenoidal surgery (EETS). Given the increasing importance of complications in quality-based healthcare metrics, the objective of this study was to assess whether Medicaid insurance type influences outcomes in EETS for pituitary adenoma. METHODS: The authors analyzed a prospectively acquired database of EETS for pituitary adenoma from 2005 to 2018 at NewYork-Presbyterian Hospital, Weill Cornell Medicine. All patients with Medicaid insurance were identified. As a control group, the clinical, socioeconomic, and radiographic data of all other patients in the series with non-Medicaid insurance were reviewed. Statistical significance was determined with an alpha < 0.05 using Pearson chi-square and Fisher's exact tests for categorical variables and the independent-samples t-test for continuous variables. RESULTS: Of 584 patients undergoing EETS for pituitary adenoma, 57 (10%) had Medicaid insurance. The maximum tumor diameter was significantly larger for Medicaid patients (26.1 ± 12 vs 23.1 ± 11 mm for controls, p < 0.05). Baseline comorbidities including diabetes mellitus, hypertension, smoking history, and BMI were not significantly different between Medicaid patients and controls. Patients with Medicaid insurance had a significantly higher rate of any complication (14% vs 7% for controls, p < 0.05) and long-term cranial neuropathy (5% vs 1% for controls, p < 0.05). There were no statistically significant differences in endocrine outcome or vision outcome. The mean postoperative length of stay was significantly longer for Medicaid patients compared to the controls (9.4 ± 31 vs 3.6 ± 3 days, p < 0.05). This difference remained significant even when accounting for outliers (5.6 ± 2.5 vs 3.0 ± 2.7 days for controls, p < 0.05). The most common causes of extended length of stay greater than 1 standard deviation for Medicaid patients were management of perioperative complications and disposition challenges. The rate of 30-day readmission was 7% for Medicaid patients and 4.4% for controls, which was not a statistically significant difference. CONCLUSIONS: The authors found that larger tumor diameter, longer postoperative length of stay, higher rate of complications, and long-term cranial neuropathy were significantly associated with Medicaid insurance. There were no statistically significant differences in baseline comorbidities, apoplexy, endocrine outcome, vision outcome, or 30-day readmission.

Endoscopic Endonasal Transclival Resection of a Pontine Metastasis: Case Report and Operative Video.

BACKGROUND AND IMPORTANCE: Brainstem lesions are challenging to manage, and surgical options have been controversial. Stereotactic radiosurgery (SRS) has been used for local control, but life-threatening toxicities from 0% to 9.5% have been reported. Several microsurgical approaches involving safe entry zones have been developed to optimize the exposure and minimize complications in different portions of the brainstem, but require extensive drilling and manipulation of neurovascular structures. With recent advancements, the endoscopic endonasal approach (EEA) can provide direct visualization of ventral brainstem. No case has been reported of EEA to remove a brainstem metastasis. CLINICAL PRESENTATION: We present an illustrative case of a 68-yr-old female with metastatic colon cancer who presented with 2.8 × 2.7 × 2.1 cm (7.9 cm3) heterogeneously enhancing, right ventral pontine lesion with extensive edema. She underwent endoscopic endonasal transclival approach, and gross total resection of the lesion was achieved. CONCLUSION: The endoscopic approach may offer certain advantages for removal of ventral brainstem lesions, as it can provide direct visualization of important neurovascular structures, especially, if the lesion displaces the tracts and comes superficial to the pial surface.

Endoscopic endonasal resection of giant pediatric craniopharyngioma: impact on hypothalamic edema.

An 8-year-old child presented with fatigue, weight loss, and visual deterioration. MRI demonstrated a craniopharyngioma with compression of the optic chiasm and extensive edema on the hypothalamus and optic radiations. The tumor was completely removed via an endoscopic endonasal approach. Postoperatively, vision improved and hypothalamic edema completely resolved within 5 days. This video demonstrates the technical nuances of the surgery and discusses the impact of surgery on the hypothalamic nuclei in pediatric patients. The video can be found here: https://youtu.be/wxkBmhTPi6c.

T Cell Primary Effusion Lymphoma in an HIV-Negative Man with Liver Cirrhosis.

BACKGROUND Primary effusion lymphoma (PEL) is a rare and aggressive non-Hodgkin lymphoma (NHL) that is responsible for 1% of all lymphomas not related to human immunodeficiency virus (HIV). PEL is characterized by human herpesvirus-8 (HHV-8) positivity in the absence of overt tumor burden that does not exhibit typical B cell or T cell immunophenotype characteristics. The exact mechanism of development is unknown, but it is hypothesized to develop from post-germinal B cell origin. Although it is most common in HIV patients, other immunocompromising comorbidities can be seen in conjunction with PEL, including liver cirrhosis. CASE REPORT We present the case of a 73-year-old HIV-seronegative man with alcohol-induced liver cirrhosis who was found to have T cell PEL of the pleural space diagnosed by thoracentesis. CONCLUSIONS Little is known regarding oncogenesis of T cell PEL, and few studies exist regarding appropriate treatment regimens for PEL as a whole, prompting need for further investigation and discussion to improve survival rates. Even in the absence of active HIV infection, PEL should be considered as a potential cause of pleural effusion in cirrhotic patients in order to prompt earlier treatment for the best chance of survival.

Endoscopic endonasal approach for suprasellar meningiomas: introduction of a new scoring system to predict extent of resection and assist in case selection with long-term outcome data.

OBJECTIVE: The endoscopic endonasal approach (EEA) has gained increasing popularity for the resection of suprasellar meningiomas (SSMs). Appropriate case selection is critical in optimizing patient outcome. Long-term outcome data are lacking. The authors systematically identified preoperative factors associated with extent of resection (EOR) and determined the relationship between EOR and long-term recurrence after EEA for SSMs. METHODS: In this retrospective cohort study, the authors identified preoperative clinical and imaging characteristics associated with EOR and built on the recently published University of California, San Francisco resectability score to propose a score more specific to the EEA. They then examined the relationship between gross-total resection (GTR; 100%), near-total resection (NTR; 95%-99%), and subtotal resection (STR; < 95%) and recurrence or progression with Kaplan-Meier survival analysis. RESULTS: A total of 51 patients were identified. Radiographic GTR was achieved in 40 of 47 (85%) patients in whom it was the surgical goal. Significant independent risk factors for incomplete resection were prior surgery (OR 25.94, 95% CI < 2.00 to 336.49, p = 0.013); tumor lateral to the optic nerve (OR 13.41, 95% CI 1.82-98.99, p = 0.011); and complete internal carotid artery (ICA) encasement (OR 15.12, 95% CI 1.17-194.08, p = 0.037). Tumor size and optic canal invasion were not significant risk factors after adjustment for other variables. A resectability score based on the multivariable model successfully predicted the likelihood of GTR; a score of 0 had a positive predictive value of 97% for GTR, whereas a score of 2 had a negative predictive value of 87.5% for incomplete resection. After a mean follow-up of 40.6 ± 32.4 months (mean ± SD), recurrence was 2.7% after GTR (1 patient with atypical histology), 44.4% after NTR, and 80% after STR (p < 0.0001). Vision was stable or improved in 93.5% and improved in 67.4% of patients with a preoperative deficit. There were 5 (9.8%) postoperative CSF leaks, of which 4 were managed with lumbar drains and 1 required a reoperation. CONCLUSIONS: The EEA is a safe and effective approach to SSMs, with favorable visual outcomes in well-selected cases. The combination of postoperative MRI-based EOR with direct endoscopic inspection can be used in lieu of Simpson grade to predict recurrence. GTR dramatically reduces recurrence and can be achieved regardless of tumor size, proximity or encasement of the anterior cerebral artery, or medial optic canal invasion. Risk factors for incomplete resection include prior surgery, tumor lateral to the optic nerve, and complete ICA encasement.

Occipital Condyle Screw Placement in Patients with Chiari Malformation: A Radiographic Feasibility Analysis and Cadaveric Demonstration.

OBJECTIVE: Patients who undergo decompression surgery for Chiari malformation frequently require occipitocervical fixation. This is typically performed with occipital plates, which may cause intracranial injuries due to multiple fixation points. We undertook this study to assess the feasibility of occipital condyle (OC) screw placement as an alternative method of occipitocervical fixation in this patient population. METHODS: Using a cadaveric model with navigational assistance, we performed the complete surgical procedure for occipitocervical fixation with OC screws. We then performed a morphometric analysis using measurements from computed tomography scans of 49 patients (32 adult, 17 pediatric) who had undergone occipitocervical fusion with instrumentation following decompression surgery for Chiari malformation. Bilateral morphometric data were analyzed for the adult and pediatric subgroups separately, as well as for the overall group. RESULTS: The surgical procedure was successfully performed in the cadaveric model, demonstrating the feasibility of the proposed method. Ninety-eight OCs were studied in the morphometric analysis, and 80 (81.6%) met our eligibility criteria for OC screw placement. However, in 14.1% of adult OCs and 26.5% of pediatric OCs studied, placement of condylar screws would have been challenging or unsafe, according to our criteria. CONCLUSIONS: Our findings suggest that OC screws provide a useful option for occipitocervical fixation in a substantial proportion of patients with Chiari malformation. However, rigorous preoperative analysis would be essential to identify appropriate candidates for this technique and exclude those in whom it should not be attempted. Additional study is warranted.

Long-term outcomes after endoscopic endonasal surgery for nonfunctioning pituitary macroadenomas.

OBJECTIVE: Nonfunctioning pituitary adenomas are benign, slow-growing tumors. After gross-total resection (GTR) or subtotal resection (STR), tumors can recur or progress and may ultimately require additional intervention. A greater understanding of long-term recurrence and progression rates following complete or partial resection and the need for further intervention will help clinicians provide meaningful counsel for their patients and assist data-driven decision-making. METHODS: The authors retrospectively analyzed their institutional database for patients undergoing endoscopic endonasal surgery (EES) for nonfunctioning pituitary macroadenomas (2003-2014). Only patients with follow-up of at least 5 years after surgery were included. Tumor volumes were measured on pre- and postoperative MRI. Tumor recurrence was defined as the presence of a 0.1-cm3 tumor volume after GTR, and tumor progression was defined as a 25.0% increase in residual tumor after STR. RESULTS: A total of 190 patients were included, with a mean age of 63.8 ± 13.2 years; 79 (41.6%) were female. The mean follow-up was 75.0 ± 18.0 months. GTR was achieved in 127 (66.8%) patients. In multivariate analysis, age (p = 0.04), preoperative tumor volume (p = 0.03), Knosp score (p < 0.001), and Ki-67 (p = 0.03) were significant predictors of STR. In patients with GTR, the probability of recurrence at 5 and 10 years was 3.9% and 4.7%, and the probability of requiring treatment for recurrence was 0.79% and 1.6%, respectively. In 63 patients who underwent STR, 6 (9.5%) received early postoperative radiation and did not experience progression, while the remaining 57 (90.5%) were observed. Of these, the probability of disease progression at 5 and 10 years was 21% and 24.5%, respectively, and the probability of requiring additional treatment for progression was 17.5% and 21%. Predictors of recurrence or progression in the entire group were Knosp score (p < 0.001) and elevated Ki-67 (p = 0.03). Significant predictors of progression after STR in those who did not receive early radiotherapy were cavernous sinus location (p < 0.05) and tumor size > 1.0 cm3 (p = 0.005). CONCLUSIONS: Following GTR for nonfunctioning pituitary adenomas, the 10-year chance of recurrence is low and the need for treatment even lower. After STR, although upfront radiation therapy may prevent progression, even without radiotherapy, the need for intervention at 10 years is only approximately 20% and a period of observation may be warranted to prevent unnecessary prophylactic radiation therapy. Tumor volume > 1 cm3, Knosp score ≥ 3, and Ki-67 ≥ 3% may be useful metrics to prompt closer follow-up or justify early prophylactic radiation therapy.

How long is the tail end of the learning curve? Results from 1000 consecutive endoscopic endonasal skull base cases following the initial 200 cases.

OBJECTIVE: Endoscopic endonasal approaches (EEAs) to the skull base have evolved over the last 20 years to become an essential component of a comprehensive skull base practice. Many case series show a learning curve from the earliest cases, in which the authors were inexperienced or were not using advanced closure techniques. It is generally accepted that once this learning curve is achieved, a plateau is reached with little incremental improvement. Cases performed during the early steep learning curve were eliminated to examine whether the continued improvement exists over the "tail end" of the curve. METHODS: A prospectively acquired database of all EEA cases performed by the senior authors at Weill Cornell Medicine/NewYork-Presbyterian Hospital was reviewed. The first 200 cases were eliminated and the next 1000 consecutive cases were examined to avoid the bias created by the early learning curve. RESULTS: Of the 1000 cases, the most common pathologies included pituitary adenoma (51%), meningoencephalocele or CSF leak repair (8.6%), meningioma (8.4%), craniopharyngioma (7.3%), basilar invagination (3.1%), Rathke's cleft cyst (2.8%), and chordoma (2.4%). Use of lumbar drains decreased from the first half to the second half of our series (p <0.05) as did the authors' use of fat alone (p <0.005) or gasket alone (p <0.005) for dural closure, while the use of a nasoseptal flap increased (p <0.005). Although mean tumor diameter was constant (on average), gross-total resection (GTR) increased from 60% in the first half to 73% in the second half (p <0.005). GTR increased for all pathologies but most significantly for chordoma (56% vs 100%, p <0.05), craniopharyngioma (47% vs 0.71%, p <0.05) and pituitary adenoma (67% vs 75%, p <0.05). Hormonal cure for secreting adenomas also increased from 83% in the first half to 89% in the second half (p <0.05). The rate of any complication was unchanged at 6.4% in the first half and 6.2% in the latter half of cases, and vascular injury occurred in only 0.6% of cases. Postoperative CSF leak occurred in 2% of cases and was unchanged between the first and second half of the series. CONCLUSIONS: This study demonstrates that contrary to popular belief, the surgical learning curve does not plateau but can continue for several years depending on the complexity of the endpoints considered. These findings may have implications for clinical trial design, surgical education, and patient safety measures.

Readmission after endoscopic transsphenoidal pituitary surgery: analysis of 584 consecutive cases.

OBJECTIVE: Hospital readmission is a key component in value-based healthcare models but there are limited data about the 30-day readmission rate after endonasal endoscopic transsphenoidal surgery (EETS) for pituitary adenoma. The objective of this study was to determine the incidence and identify factors associated with 30-day readmission after EETS for pituitary adenoma. METHODS: The authors analyzed a prospectively acquired database of patients who underwent EETS for pituitary adenoma from 2005 to 2018 at NewYork-Presbyterian Hospital, Weill Cornell Medicine. Clinical, socioeconomic, and radiographic data were reviewed for cases of unplanned readmission within 30 days of surgery and, as a control group, for all other patients in the series who were not readmitted. Statistical significance was determined with an alpha < 0.05 using Pearson's chi-square and Fisher's exact tests for categorical variables and the independent-samples t-test for continuous variables. RESULTS: Of 584 patients undergoing EETS for pituitary adenoma, 27 (4.6%) had unplanned readmission within 30 days. Most readmissions occurred within the first week after surgery, with a mean time to readmission of 6.6 ± 3.9 days. The majority of readmissions (59%) were for hyponatremia. These patients had a mean sodium level of 120.6 ± 4.6 mEq/L at presentation. Other causes of readmission were epistaxis (11%), spinal headache (11%), sellar hematoma (7.4%), CSF leak (3.7%), nonspecific headache (3.7%), and pulmonary embolism (3.7%). The postoperative length of stay was significantly shorter for patients who were readmitted than for the controls (2.7 ± 1.0 days vs 3.9 ± 3.2 days; p < 0.05). Patients readmitted for hyponatremia had an initial length of stay of 2.6 ± 0.9 days, the shortest of any cause for readmission. The mean BMI was significantly lower for readmitted patients than for the controls (26.4 ± 3.9 kg/m2 vs 29.3 ± 6.1 kg/m2; p < 0.05). CONCLUSIONS: Readmission after EETS for pituitary adenoma is a relatively rare phenomenon, with delayed hyponatremia being the primary cause. The study results demonstrate that shorter postoperative length of stay and lower BMI were associated with 30-day readmission.