PATH-13. INTRAOPERATIVE EVALUATION OF IDH MUTATION STATUS AND TUMOR INVASION IN GLIOMA

BACKGROUND Intraoperative detection of residual tumor and isocitrate dehydrogenase (IDH) mutations can assist in maximizing surgical resection beyond contrast enhancing margins and guide intraoperative surgical decision making for glioma patients. We aimed to evaluate the use of desorption electrospray ionization-mass spectrometry (DESI-MS) for intraoperative assessment of IDH mutations and estimation of tumor cell percentage (TCP). METHODS This is a prospective study using intraoperative DESI-MS analysis of freshly obtained tissue samples to evaluate IDH mutations via 2-hydroxyglutarate (2-HG) intensity and TCP via measurement of N-acetylaspartic acid (NAA) intensity and characteristic lipid profiles. These IDH mutation and TCP estimates were subsequently validated by a senior neuropathologist. RESULTS A total of 247 biopsies from a 49-patient study were previously collected and analyzed at Indiana University. Assessment of TCP in 203 margin and core biopsies based on NAA intensity yielded sensitivity, specificity, and accuracy values of 91, 76, and 83%, whereas TCP assessment based on characteristic lipid profiles yielded 76, 85, and 81%, respectively. Assessment of IDH mutation status of 71 core biopsies yielded sensitivity, specificity, and accuracy values of 89, 100, and 94%. Further validation of the methodology is being performed in an ongoing collaboration with Mayo Clinic-Jacksonville, where we have collected 178 biopsies from 24 patients. Preliminary results of IDH mutation assessments indicate 100% sensitivity, specificity, and accuracy. DISCUSSION/CONCLUSION We present a novel system to allow intraoperative evaluation of IDH status and to guide surgical resection by TCP measurement from tissue biopsies. Prospectively, we propose to modify our DESI-MS system by placing a surgical material (e.g. cottonoid) along the surgical margin and transferring material from the blot to a microscope slide prior to DESI-MS analysis. This will allow the retention of the spatial distribution of diagnostic molecules while analyzing a wall of the surgical cavity without the need for biopsy.

Assessment and Management of Acute Volar Rim Fractures

The volar rim of the distal radius is the only bony restraint to volar carpal subluxation. Higher loads across the volar rim require stable and rigid fixation to maintain reduction and allow healing while rehabilitation begins. Volar marginal fragments are not amenable to buttressing by fixed angle volar locking plates. Appropriate management of volar marginal fragments comprises two steps—recognition of their presence and rigid anatomical repair. The best opportunity for success in the presence of a volar marginal fragment is its adequate initial treatment. The purpose of this review is to reinforce the importance of a complete preoperative and intraoperative evaluation of distal radius fractures. Volar marginal fragments can easily be overlooked even following initial reduction and fixation. Understanding the relevant anatomy and loading parameters can facilitate intraoperative decisions on approach and fixation, which are integral to achieving optimal clinical outcomes.

Somatotroph Adenomas have a Predilection to Invade the Cavernous Sinus and Resection of the Medial Wall of the Cavernous Sinus Offers the Highest Potential for Biochemical Remission in Acromegaly

Recurrence and remission rates vary widely among different histological subtypes of pituitary adenoma. Invasion of the medial wall of the cavernous sinus is a known mechanism that may account for such failed clinical outcomes as its removal has long been considered unattainable. The use of modern endoscopic techniques allows for direct intraoperative evaluation of invasion and resection of the medial wall of the cavernous sinus with low morbidity when performed by highly experienced surgeons. In this retrospective study we evaluated 105 consecutive primary pituitary adenomas operated by a single surgeon including 28 corticotroph, 27 gonadotroph, 24 somatotroph, 15 lactotroph, 5 null-cell, 5 plurihormonal, and 1 dual adenoma; 53 caused hypersecretory syndromes, specifically acromegaly (30), hyperprolactinemia (15) and Cushing’s disease (8). In each case, we performed meticulous intraoperative inspection of the medial wall with its surgical removal when invasion was suspected, regardless of functional status. Medial wall resection was performed in 46% of pituitary adenomas, and 38/48 walls confirmed pathologic evidence of invasion rendering a positive predictive value of intraoperative evaluation of medial wall invasion of 79%. Furthermore, we show for the first time that the rate of medial wall invasion among pathological subtypes is dramatically different. Somatotroph tumors invaded the medial wall much more often than other adenoma subtypes, 83% intraoperatively and 71% histologically, followed by plurihormonal tumors (40%) and gonadotrophs (33%), both with intraoperative positive predictive value of 100%. The least likely to invade were corticotroph, at a rate of 32% intraoperatively and 21% histologically, and null-cell adenomas at 0%. Removal of the medial wall caused no permanent morbidity with no carotid artery injuries and 2 patients with transient diplopia. We report that resecting the medial wall of the cavernous sinus in acromegaly offers the highest potential for biochemical remission with average postoperative day 1 GH levels at 0.96 ug/l and early surgical remission rates at 90% (100% with adjuvant therapy) based on normalization of IGF-1 levels 3 to 6 months after surgery; these results are significantly better than previously reported but longer follow-up is required for definitive conclusions. Our findings may explain the failed biochemical remission rates seen in acromegaly and illustrate the relevance of advanced surgical techniques for successful outcomes in pituitary surgery.

A Modified Approach to Transconjuntival Levator Advancement Offering Intraoperative Options

Background The transconjunctival technique is a preferable and beneficial approach in mild to moderate blepharoptosis repair as without skin incision. However, accurate surgical manipulation of this method is greatly restricted by the poor intraoperative evaluation. Objectives To introduce a modified transconjunctival approach with flexible intraoperative adjustments in order to achieve more accurate ptosis correction. Methods By transconjunctival approach, the levator aponeurosis and the Müller’s muscle were folded using a square-like mattress suture for flexible adjustment and accurate correction. Results In 18 mild ptosis eyelids, 94.5% (17 eyelids) achieved adequate or normal correction. In 9 eyelids with moderate ptosis, 88.9% (8 eyelids) achieved adequate or normal correction. Amongst 24 ptosis patients, 23 (95.8%) achieved good or fair symmetry result. Conclusion We presented a modified transconjunctival technique for repair of mild to moderate ptosis, which is characterized by flexible intraoperative adjustments achieving both satisfying functional and aesthetic outcomes.