1-Piece Versus 2-Piece Fronto-Temporo-Orbito-Zygomatic Craniotomy: A Narrative Overview of Evolution.

BACKGROUND: The fronto-temporo-orbito-zygomatic (FTOZ) craniotomy is a commonly utilized surgical approach for many complex skull base lesions, especially lesions traversing skull base compartments. This craniotomy has evolved over multiple stages, originating from the classic pterional craniotomy and many variations that have emerged over time. METHODS: Few clinical and anatomic studies have both shaped these craniotomies as well as provided immense information about instances in which they are most useful. We review the origin and history of the one-piece and two-piece fronto-temporo-orbito-zygomatic craniotomy and deliberate their advantages and disadvantages. RESULTS: The FTOZ craniotomy provides access to the orbit as well as to multiple compartments in the cranium (anterior, middle and upper third posterior cranial fossae); thus, offering a multi-corridor approach to complex skull base lesions. The one-piece and two-piece fronto-temporo-orbitozygomatic craniotomies are two particularly notable variations that have stood the test of time. Selection between the two variations is mostly surgeon preference and comfort with the technique; however, there are certain indications that specifically suit each approach. Additionally, a pictorial review has been crafted to clearly illustrate the cuts to be made in both methods. CONCLUSION: Understanding the evolution of this craniotomy and surgical approach provides an insight into accessing complex skull base pathologies with minimal brain retraction via safe and viable corridors.

Utility of hospital frailty risk score for predicting postoperative outcomes in craniopharyngioma.

OVERVIEW: Frailty is an age-associated decline in functional status leading to increased vulnerability to otherwise innocuous stressors. In neurosurgical patients, frailty has been associated with postoperative complications, increased mortality, longer hospitalization, and increased care costs for a variety of conditions. This study seeks to determine the association between frailty and postoperative outcomes in patients undergoing surgery for craniopharyngioma. METHODS: The Nationwide Inpatient Sample (NIS) database was queried for patients diagnosed with craniopharyngioma who underwent surgery via either craniotomy or transsphenoidal approach. Comorbid diagnoses were used to calculate the Hospital Frailty Risk Score (HFRS) and assign patients to low (< 5), intermediate (5-15), or high-risk (> 15) categories. Logistic regression was completed to determine whether the HFRS category was predictive of mortality, postoperative complication, extended hospitalization, or increased hospital costs compared to age. RESULTS: Increased frailty score was predictive of increased length of stay, increased hospital costs, and non-home discharge in binary logistic regression with good discrimination on the ROC curve compared to age at admission. HFRS risk categories were significantly predictive of the development of any complication, with 100% of high-risk patients developing a complication compared to 76% of intermediate-risk and 63% of low-risk patients. HFRS risk categories were also predictive of the extended length of stay (71%, 49%, and 11% for high-, intermediate-, and low-risk, respectively) and non-home discharge (86%, 56%, and 17%). Regression analysis was unable to be performed for mortality due to the low number of deaths in the study group. CONCLUSION: In patients undergoing any surgery for craniopharyngioma, frailty is predictive of increased hospital length of stay and overall care costs. HFRS failed to independently predict mortality because the incidence of mortality is too low in this population to analyze. The HFRS is a valuable tool to identify post-operative outcomes following surgery for craniopharyngioma.

Temporal Control of Gelation and Polymerization Fronts Driven by an Autocatalytic Enzyme Reaction.

Chemical systems that remain kinetically dormant until activated have numerous applications in materials science. Herein we present a method for the control of gelation that exploits an inbuilt switch: the increase in pH after an induction period in the urease-catalyzed hydrolysis of urea was used to trigger the base-catalyzed Michael addition of a water-soluble trithiol to a polyethylene glycol diacrylate. The time to gelation (minutes to hours) was either preset through the initial concentrations or the reaction was initiated locally by a base, thus resulting in polymerization fronts that converted the mixture from a liquid into a gel (ca. 0.1 mm min-1). The rate of hydrolytic degradation of the hydrogel depended on the initial concentrations, thus resulting in a gel lifetime of hours to months. In this way, temporal programming of gelation was possible under mild conditions by using the output of an autocatalytic enzyme reaction to drive both the polymerization and subsequent degradation of a hydrogel.

Temporal Control of Gelation and Polymerization Fronts Driven by an Autocatalytic Enzyme Reaction.

Chemical systems that remain kinetically dormant until activated have numerous applications in materials science. Herein we present a method for the control of gelation that exploits an inbuilt switch: the increase in pH after an induction period in the urease-catalyzed hydrolysis of urea was used to trigger the base-catalyzed Michael addition of a water-soluble trithiol to a polyethylene glycol diacrylate. The time to gelation (minutes to hours) was either preset through the initial concentrations or the reaction was initiated locally by a base, thus resulting in polymerization fronts that converted the mixture from a liquid into a gel (ca. 0.1 mm min(-1)). The rate of hydrolytic degradation of the hydrogel depended on the initial concentrations, thus resulting in a gel lifetime of hours to months. In this way, temporal programming of gelation was possible under mild conditions by using the output of an autocatalytic enzyme reaction to drive both the polymerization and subsequent degradation of a hydrogel.