Arteriovenous Access superficialization: A New Technique and Review of Options.

BACKGROUND: Up to 30% of autogenous cephalic vein arteriovenous fistulas (AVFs) are too deep for reliable cannulation. Techniques to superficialize these AVFs have been described previously. This study describes a new surgical technique for AVF superficialization and provides a review of the alternative techniques. METHODS: The path of the fistula is marked using ultrasound, and transverse incisions are made along this path. The underlying tissue is separated from the dermis over this area to expose the fistula outflow vein. The mobilized vein is then elevated and "trapped" directly under the dermis by closing the superficial fascia and adipose tissue beneath it. RESULTS: Between March 2016 and February 2019, 23 patients underwent superficialization using this technique at two centers. The mean time between AVF creation and superficialization was 6.3 months, and the time to first use for hemodialysis after superficialization was 38.8 ± 27.9 days. The average presuperficialization depth was 7.1 ± 2.4 mm and average postsuperficialization depth was 3.7 ± 2.7 mm (P = 0.002). Sixteen fistulas were successfully accessed for a cannulation rate of 89%. 94.7% of fistulas remained patent at last visit, with only one thrombosed 8-10 weeks after superficialization. CONCLUSIONS: This technique appears to be both safe and effective, and results in a vein that is immediately subdermal without major contour deformity. Early outcomes are comparable to those alternative methods described in the literature.

Risk Factors for Intraoperative and Postoperative Cerebrospinal Fluid Leaks in Endoscopic Transsphenoidal Sellar Surgery.

Objective To determine the factors associated with intra- and postoperative cerebrospinal fluid (CSF) leaks in setting of endoscopic transsphenoidal sellar surgery. Study Design Retrospective cohort. Setting Tertiary referral center. Subjects and Methods This study included 806 patients who underwent endoscopic transsphenoidal sellar surgery between 2004 and 2016. The associations between CSF leaks (intra- and postoperative) and patient demographics, medical history, tumor characteristics, and intraoperative repair techniques were analyzed. Results In sum, 205 (25.4%) patients had a CSF leak: 188 (23.3%) intraoperative leaks and 38 (4.7%) postoperative leaks. Twenty-one (2.6%) patients had postoperative leaks after having repair of an intraoperative leak; 55% of patients with a postoperative leak had an intraoperative leak repaired. On multivariate analysis, body mass index (BMI), hydrocephalus, suprasellar extension, and craniopharyngioma significantly predicted intraoperative CSF leaks, while only BMI and hydrocephalus predicted postoperative CSF leaks. Patients having septal flap repairs of CSF leaks had a higher postoperative leak rate relative to other repair techniques (odds ratio, 6.37; P = .013). Rigid reconstruction did not correlate with leaks. Conclusion For this large cohort of patients undergoing endoscopic transsphenoidal sellar surgery, BMI and hydrocephalus were identified as predictors of postoperative CSF leaks, including those occurring after repair of intraoperative leak. These variables may put stress on the surgical repair of sellar defects, and consideration of these risk factors may help counsel patients and guide perioperative decision making in regard to repair strategies and CSF diversion techniques.