Intraocular Pressure Changes during Laparoscopic Surgery in Trendelenburg Position in Patients Anesthetized with Propofol-based Total Intravenous Anesthesia Compared to Sevoflurane Anesthesia: A Comparative Study

[Small tidal volume hyperventilation relieves intraocular and intracranial pressure elevation in prone spinal surgery: a randomized controlled trial]

OBJECTIVE

To investigate the effects of different ventilation strategies on intraocular pressure (IOP) and intracranial pressure in patients undergoing spinal surgery in the prone position under general anesthesia.

METHODS

Seventy-two patients undergoing prone spinal surgery under general anesthesia between November, 2022 and June, 2023 were equally randomized into two groups to receive routine ventilation (with Vt of 8mL/kg, Fr of 12-15/min, and etCO2 maintained at 35-40 mmHg) or small tidal volume hyperventilation (Vt of 6 mL/kg, Fr of18-20/min, and etCO2 maintained at 30-35 mmHg) during the surgery. IOP of both eyes (measured with a handheld tonometer), optic nerve sheath diameter (ONSD; measured at 3 mm behind the eyeball with bedside real-time ultrasound), circulatory and respiratory parameters of the patients were recorded before anesthesia (T0), immediately after anesthesia induction (T1), immediately after prone positioning (T2), at 2 h during operation (T3), immediately after supine positioning after surgery (T4) and 30 min after the operation (T5).

RESULTS

Compared with those at T1, IOP and ONSD in both groups increased significantly at T3 and T4(P < 0.05). IOP was significantly lower in hyperventilation group than in routine ventilation group at T3 and T4(P < 0.05), and ONSD was significantly lower in hyperventilation group at T4(P < 0.05). IOP was positively correlated with the length of operative time (r=0.779, P < 0.001) and inversely with intraoperative etCO2 at T3(r=-0.248, P < 0.001) and T4(r=-0.251, P < 0.001).ONSD was correlated only with operation time (r=0.561, P < 0.05) and not with IOP (r=0.178, P>0.05 at T3; r=0.165, P>0.05 at T4).

CONCLUSION

Small tidal volume hyperventilation can relieve the increase of IOP and ONSD during prone spinal surgery under general anesthesia.

Parenthood and neurosurgery in Europe a white paper from the European Association of Neurosurgical Societies' Diversity in Neurosurgery Committee Part I - Family Planning and Practice during Pregnancy

Introduction

Family and work have immensely changed and become intertwined over the past half century for both men and women. Additionally, alongside to traditional family structures prevalent, other forms of families such as single parents, LGBTQ + parents, and bonus families are becoming more common. Previous studies have shown that surgical trainees regularly leave residency when considering becoming a parent due to the negative stigma associated with pregnancy during training, dissatisfaction with parental leave options, inadequate lactation and childcare support, and desire for greater mentorship on work-life integration. Indeed, parenthood is one of the factors contributing to attrition in surgical specialities, neurosurgery not being an exception.

Research question

The Diversity in Neurosurgery Committee (DC) of the European Association of Neurosurgical Societies (EANS) recognizes the challenges individuals face in parenthood with neurosurgery and wishes to address them in this white paper.

Materials and methods

In the following sections, the authors will focus on the issues pertaining to family planning and neurosurgical practice during pregnancy in itemized fashion based on an exhaustive literature search and will make recommendations to address the matters raised.

Results

Potential solutions would be to further improve the work-family time ration as well as improving working conditions in the hospital.

Discussion and conclusion

While many obstacles have been quoted in the literature pertaining to parenthood in medicine, and in neurosurgery specifically, initiatives can and should be undertaken to ensure not only retention of colleagues, but also to increase productivity and job satisfaction of those seeking to combine neurosurgery and a family life, regardless of their sexual identity and orientation.

Effect of sevoflurane, propofol and propofol with dexmedetomidine as maintenance agent on intracranial pressure in the Trendelenburg position during laparoscopic surgeries

Background and Aim

Pneumoperitoneum (PP) and the Trendelenburg position (TP) in laparoscopic surgeries are associated with rise in intracranial pressure (ICP). The optic nerve sheath diameter (ONSD) is a surrogate marker of ICP. The study aimed to evaluate the effect of sevoflurane, propofol and propofol with dexmedetomidine as maintenance agent on ICP in TP during laparoscopic surgeries.

Material and Methods

A total of 120 American Society of Anesthesiologists (ASA) physical status I/II patients, aged 18-65 years were randomly allocated into three groups: sevoflurane as group S, propofol as group P, and propofol with dexmedetomidine as group PD. The intra-abdominal pressure (IAP) was kept in the range of 12-14 mmHg and TP varied between 15°- 45° angle. The primary objective was comparison of ICP and secondary objectives were IOP, intraoperative hemodynamic and postoperative recovery characteristics among groups. The ONSD and IOP were measured in both eyes 10 min after endotracheal intubation (T0), 5 min after CO2 insufflation (T1), 5 min after TP (T2) and 5 min after deflation of gas (T3). The data were analyzed by using the Statistical Package for Social Sciences version 23.

Results

ONSD and IOP at T1 and T2 were significantly higher than T0 in all groups, but no significant difference was found among the intergroup groups. Significantly lower heart rate and mean blood pressure were observed in PD group at T1 and T2 compared to group S and group P.

Conclusion

The rise in ICP was comparable among sevoflurane, propofol, and propofol-dexmedetomidine combination as a maintenance agent during laparoscopic surgeries in TP.

The Impact of Steep Trendelenburg Position on Intraocular Pressure

Intraocular pressure occurring during the Trendelenburg position may be a risk for postoperative visual loss and other ocular complications. Intraocular pressure (IOP) higher than 21 mmHg poses a risk for ocular impairment causing several conditions such as glaucoma, detached retina, and postoperative vision loss. Many factors might play a role in IOP increase, like peak expiratory pressure (PIP), mean arterial blood pressure (MAP), end-tidal CO2 (ETCO2) and surgical duration and some others (anaesthetic and neuromuscular blockade depth) contribute by reducing IOP during procedures requiring both pneumoperitoneum and steep Trendelenburg position (25-45° head-down tilt). Despite transient visual field loss after surgery, no signs of ischemia or changes to the retinal nerve fibre layer (RNFL) have been shown after surgery. Over the years, several studies have been conducted to control and prevent IOPs intraoperative increase. Multiple strategies have been proposed by different authors over the years to reduce IOP during laparoscopic procedures, especially those involving steep Trendelenburg positions such as robot-assisted laparoscopic prostatectomy (RALP), and abdominal and pelvic procedures. These strategies included both positional and pharmacological strategies.

The effect of anesthetic agents on intraocular pressure during laparoscopic gynecological surgery performed in the Trendelenburg position: A randomized clinical trial

BACKGROUND

Intraocular pressure (IOP) increases due to pneumoperitoneum and the Trendelenburg position during laparo-scopic surgery. Apart from ketamine and suxamethonium, anesthetic agents generally reduce IOP by various extents. The present study investigated the effects of combinations of four anesthetic agents on IOP during laparoscopic gynecological surgery.

METHODS

Patients (n=100) were assigned to one of the four groups: Group 1 (n=25; pentothal induction + desflurane/remifen-tanil maintenance), Group 2 (n=25; propofol induction + sevoflurane/remifentanil maintenance), Group 3 (n=25; propofol induction + desflurane/remifentanil maintenance), and Group 4 (n=25; pentothal induction + sevoflurane/remifentanil maintenance). The IOPs recorded before anesthesia induction, after intubation, after carbon dioxide insufflation, in the Trendelenburg position, and after ex-tubation were compared among the groups. Hemodynamic parameters were also evaluated.

RESULTS

Induction in Group 2 and Group 3 used propofol. When the IOP in the Trendelenburg position was compared with the IOP before induction, there was no statistically significant difference in Groups 2 and 3 (p>0.05). In Groups 1 and 4, pentothal was used for induction. The IOP in Groups 1 and 4 was statistically significantly higher in the Trendelenburg position than it was before induction (0.027-0.001).

CONCLUSION

To minimize the variation in IOP in the Trendelenburg position during laparoscopic gynecological surgeries, we recommend the use of propofol for induction, independent of desflurane or sevoflurane use.

Clinical Anatomy of the Extradural Neural Axis Compartment: A Literature Review

OBJECTIVE

The extradural neural axis compartment (EDNAC) is an adipovenous zone located between the meningeal and endosteal layers of the dura and has been minimally investigated. It runs along the neuraxis from the orbits down to the coccyx and contains fat, valveless veins, arteries, and nerves. In the present review, we have outlined the current knowledge regarding the structural and functional significance of the EDNAC.

METHODS

We performed a narrative review of the reported EDNAC data.

RESULTS

The EDNAC can be organized into 4 regional enlargements along its length: the orbital, lateral sellar, clival, and spinal segments, with a lateral sellar orbital junction linking the orbital and lateral sellar segments. The orbital EDNAC facilitates the movement of the eyeball and elsewhere allows limited motility for the meningeal dura. The major nerves and vessels are cushioned and supported by the EDNAC. Increased intra-abdominal pressure will also be conveyed along the spinal EDNAC, causing increased venous pressure in the spine and cranium. From a pathological perspective, the EDNAC functions as a low-resistance, extradural passageway that might facilitate tumor encroachment and expansion.

CONCLUSIONS

Clinicians should be aware of the extent and significance of the EDNAC, which could affect skull base and spine surgery, and have an understanding of the tumor spread pathways and growth patterns. Comparatively little research has focused on the EDNAC since its initial description. Therefore, future investigations are required to provide more information on this underappreciated component of neuraxial anatomy.

Attenuation of increased intraocular pressure with propofol anesthesia: A systematic review with meta-analysis and trial sequential analysis

Attenuation of an increase in intraocular pressure (IOP) is crucial to preventing devastating postoperative visual loss following surgery. IOP is affected by several factors, including the physiologic alteration due to pneumoperitoneum and patient positioning and differences in anesthetic regimens. This study aimed to investigate the effects of propofol-based total intravenous anesthesia (TIVA) and volatile anesthesia on IOP. We searched multiple databases for relevant studies published before October 2019. Randomized controlled trials comparing the effects of propofol-based TIVA and volatile anesthesia on IOP during surgery were considered eligible for inclusion. Twenty studies comprising 980 patients were included. The mean IOP was significantly lower in the propofol-based TIVA group after intubation, pneumoperitoneum, Trendelenburg positioning, and lateral decubitus positioning. Moreover, mean arterial pressure and peak inspiratory pressure were also lower after intubation in the propofol-based TIVA group. Trial sequential analyses for these outcomes were conclusive. Propofol-based TIVA is more effective than volatile anesthesia during surgery at attenuating the elevation of IOP and should be considered, especially in at-risk patients.

Prospective evaluation of visual function in patients with ocular diseases after robot-assisted laparoscopic prostatectomy

OBJECTIVES

To investigate intraocular pressure and visual function in patients with ocular diseases undergoing robot-assisted laparoscopic prostatectomy.

METHODS

We carried out a prospective clinical study of patients undergoing robot-assisted laparoscopic prostatectomy for localized prostate cancer at The University of Tokyo Hospital from December 2015 to March 2017. An ophthalmologist measured intraocular pressure, and carried out visual field testing at 0-2 months before and 7 days after robot-assisted laparoscopic prostatectomy. During the surgery, an anesthesiologist measured intraocular pressure at specified time points.

RESULTS

A total of 110 patients were enrolled and 98 eligible patients were analyzed; 37 were diagnosed with ocular diseases before robotic-assisted laparoscopic prostatectomy (17 with glaucoma, 20 with other ocular diseases). Intraocular pressure significantly increased during robot-assisted laparoscopic prostatectomy. Transient postoperative visual field defect was detected in 24 eyes of 17 patients, including six patients with ocular diseases at 7 days after surgery. At 3 months after surgery, one of 34 glaucomatous eyes and one of 40 eyes with non-glaucomatous ocular diseases continued to show visual field defect, although visual field defect in the remaining patients recovered to preoperative conditions within 3 months.

CONCLUSIONS

Our findings suggest that robot-assisted laparoscopic prostatectomy can be safely carried out in patients with ocular diseases, even those with glaucoma, after precautionary consultation with an ophthalmologist.

Optic nerve sheath diameter changes during gynecologic surgery in the Trendelenburg position: comparison of propofol-based total intravenous anesthesia and sevoflurane anesthesia

Background

Elevated intracranial pressure (ICP), a disadvantage of laparoscopic or robotic surgery, is caused by the steep angle of the Trendelenburg position and the CO₂ pneumoperitoneum. Recently, sonographically measured optic nerve sheath diameter (ONSD) was suggested as a simple and non-invasive method for detecting increased ICP. This study aimed to explore the changes in ONSD in relation to different anesthetic agents used in gynecologic surgery.

Methods

Fifty patients were randomly allocated to two groups, sevoflurane (group SEV, n = 25) and propofol-based total intravenous anesthesia (TIVA) group (group TIVA, n = 25). The ONSD was measured at five time points (T0–T4): T0 was measured 5 min after induction of anesthesia in the supine position; T1, T2, and T3 were measured at 5, 15, and 30 min after CO₂ pneumoperitoneum induction in the Trendelenburg position; and T4 was measured at 5 min after discontinuation of CO₂ pneumoperitoneum in the supine position. Respiratory and hemodynamic variables were also recorded.

Results

The intra-group changes in mean ONSD in the Trendelenburg position were significantly increased in both groups. However, inter-group changes in mean ONSD were not significantly different at T0, T1, T2, T3, and T4. Heart rates in group TIVA were significantly lower than those in group SEV at points T1–T4.

Conclusions

There was no significant difference in the ONSD between the two groups until 30 min into the gynecologic surgery with CO₂ pneumoperitoneum in the Trendelenburg position. This study suggests that there is no difference in the ONSD between the two anesthetic methods.