Surgical instruments and catheter damage during ventriculoperitoneal shunt assembly.

OBJECTIVE: Current surgical techniques use common surgical instruments for sterile shunt assembly. This study investigated the impact of using these techniques and surgical instruments on the mechanical integrity of the ventriculoperitoneal shunt system, specifically shunt catheters. METHODS: The authors conducted failure testing on 85 rifampin-coated catheters and 85 barium-impregnated catheters using 5 different surgical instruments and 2 different surgical techniques. In technique A, the distal end of the catheter was pushed onto the shunt valve inlet connector with the surgical instrument. In technique B, the catheter was pulled over the inlet connector. One hundred sixty catheters underwent 10-repetition-maximum testing, in which the catheter either failed before completion of 10 consecutive assembly/disassembly repetitions or the catheter completed 10 consecutive repetitions. The authors also conducted 100-repetition-maximum tests on 5 barium-impregnated and 5 rifampin-coated catheters using technique A. RESULTS: Catheter failure rates were significantly different among the different instruments used in assembly (p ≤ 0.001). Post hoc analysis showed that using mosquito forceps with shods resulted in a significantly lower catheter failure rate than the other instruments (p < 0.0005). The catheter failure rate of technique A was significantly lower than that of technique B (5% vs 81%, p < 0.001). There was no statistical difference between the failure rates of the barium and rifampin catheters (42% vs 44%, p = 0.9), but the barium catheters outperformed the rifampin catheters in the 100-repetition-maximum trials (p = 0.02). Instrument type (p = 0.0232) and catheter type (p = 0.0096) were both significant factors in determining the number of assembly/disassembly repetitions needed to cause catheter failure. It took an average of 2.79 repetitions of assembly/disassembly to cause catheter failure. DeBakey forceps had significantly lower mean repetitions to failure (mean 1.38) than the Gerald forceps without teeth (mean 2.73, p = 0.05) and bayonet (mean 3.25, p = 0.02). CONCLUSIONS: This study was the first of its kind to analyze how physical manipulation affects the mechanical integrity of ventriculoperitoneal shunt components. The authors demonstrated a significantly lower shunt catheter failure rate when mosquito forceps with shods and technique A were used in assembly. Moreover, the authors established that use of DeBakey forceps resulted in failure with fewer assembly/disassembly repetitions than use of the Gerald and bayonet forceps, suggesting that DeBakey forceps are the most damaging instrument.

Primary Repair of Posteriorly Located Anterior Skull Base Dural Defects Using Nonpenetrating Titanium Clips in Cranial Trauma.

Objective Primary repair of posteriorly located anterior skull base (ASB) dural defects following cranial trauma is made difficult by narrow operative corridors and adherent dura mater. Inadequate closure may result in continued cerebrospinal fluid (CSF) leak and infectious sequelae. Here, we report surgical outcomes following the use of nonpenetrating titanium microclips as an adjunctive repair technique in traumatic anterior skull base dural defects extending from the olfactory groove to the tuberculum sellae. Methods All trauma patients who underwent a bifrontal craniotomy from January 2013 to October 2019 were retrospectively reviewed. Patients with ASB defects located at posterior to the olfactory groove were analyzed. Patients with isolated frontal sinus fractures were excluded. All patients presented with CSF leak or radiographic signs of dural compromise. Patients were divided according to posterior extent of injury. Patient characteristics, imaging, surgical technique, and outcomes are reported. Results A total of 19 patients who underwent a bifrontal craniotomy for repair of posteriorly located ASB dural defects using nonpenetrating titanium microclips were included. Defects were divided by location: olfactory groove (10/19), planum sphenoidale (6/19), and tuberculum sellae (3/19). No patients demonstrated a postoperative CSF leak. No complications related to the microclip technique was observed. Clip artifact did not compromise postoperative imaging interpretation. Conclusion Primary repair of posteriorly located ASB dural defects is challenging due to narrow working angles and thin dura mater. Use of nonpenetrating titanium microclips for primary repair of posteriorly located dural defects is a reasonable adjunctive repair technique and was associated with no postoperative CSF leaks in this cohort.

A systematic review of the utility of amino acid PET in assessing treatment response to bevacizumab in recurrent high-grade glioma.

BACKGROUND: Currently, bevacizumab (BEV), an antiangiogenic agent, is used as an adjunctive therapy to re-irradiation and surgery in patients with recurrent high-grade gliomas (rHGG). BEV has shown to decrease enhancement on MRI, but it is often unclear if these changes are due to tumor response to BEV or treatment-induced changes in the blood brain barrier. Preliminary studies show that amino acid PET can aid in distinguishing these changes on MRI. METHODS: The authors performed a systematic review of PubMed and Embase through July 2020 with the search terms 'bevacizumab' or 'Avastin' and 'recurrent glioma' and 'PET,' yielding 38 papers, with 14 meeting inclusion criteria. RESULTS: Thirteen out of fourteen studies included in this review used static PET and three studies used dynamic PET to evaluate the use of BEV in rHGG. Six studies used the amino acid tracer [18F]FET, four studies used [11C]MET, and four studies used [18F]FDOPA. CONCLUSION: [18F]FET, [11C]MET, and [18F]FDOPA PET in combination with MRI have shown promising results for improving accuracy in diagnosing tumor recurrence, detecting early treatment failure, and distinguishing between tumor progression and treatment-induced changes in patients with rHGG treated with BEV.

Pullulanase and Starch Synthase III Are Associated with Formation of Vitreous Endosperm in Quality Protein Maize.

The opaque-2 (o2) mutation of maize increases lysine content, but the low seed density and soft texture of this type of mutant are undesirable. Lines with modifiers of the soft kernel phenotype (mo2) called "Quality Protein Maize" (QPM) have high lysine and kernel phenotypes similar to normal maize. Prior research indicated that the formation of vitreous endosperm in QPM might involve changes in starch granule structure. In this study, we focused on analysis of two starch biosynthetic enzymes that may influence kernel vitreousness. Analysis of recombinant inbred lines derived from a cross of W64Ao2 and K0326Y revealed that pullulanase activity had significant positive correlation with kernel vitreousness. We also found that decreased Starch Synthase III abundance may decrease the pullulanase activity and average glucan chain length given the same Zpu1 genotype. Therefore, Starch Synthase III could indirectly influence the kernel vitreousness by affecting pullulanase activity and coordinating with pullulanase to alter the glucan chain length distribution of amylopectin, resulting in different starch structural properties. The glucan chain length distribution had strong positive correlation with the polydispersity index of glucan chains, which was positively associated with the kernel vitreousness based on nonlinear regression analysis. Therefore, we propose that pullulanase and Starch Synthase III are two important factors responsible for the formation of the vitreous phenotype of QPM endosperms.