The significance of intra-abdominal pressure in neurosurgery and neurological diseases: a narrative review and a conceptual proposal.

Intra-abdominal pressure (IAP) is a physiological parameter that has gained considerable attention during the last few decades. The incidence of complications arising from increased IAP, known as intra-abdominal hypertension (IAH) or abdominal compartment syndrome in critically ill patients, is high and its impact is significant. The effects of IAP in neurological conditions and during surgical procedures are largely unexplored. IAP also appears to be relevant during neurosurgical procedures (spine and brain) in the prone position, and in selected cases, IAH may affect cerebrospinal fluid drainage after a ventriculoperitoneal shunt operation. Furthermore, raised IAP is one of the contributors to intracranial hypertension in patients with morbid obesity. In traumatic brain injury, case reports described how abdominal decompression lowers intracerebral pressure. The anatomical substrate for transmission of the IAP to the brain and venous system of the spine is the extradural neural axis compartment; the first reports of this phenomenon can be found in anatomical studies of the sixteenth century. In this review, we summarize the available knowledge on how IAP impacts the cerebrospinal venous system and the jugular venous system via two pathways, and we discuss the implications for neurosurgical procedures as well as the relevance of IAH in neurological disorders.

How I do it: percutaneous transforaminal endoscopic discectomy for lumbar disk herniation.

BACKGROUND: Percutaneous transforaminal endoscopic discectomy (PTED) has emerged as a less invasive technique to treat symptomatic lumbar disk herniation (LDH). PTED is performed under local anesthesia with the advantage of immediate intraoperative feedback of the patient. In this paper, the technique is described as conducted in our hospital. METHODS: PTED is performed under local anesthesia in prone position on thoracopelvic supports. The procedure is explained stepwise: e.g. marking, incision, introduction of the 18-gauge needle and guidewire to the superior articular process, introduction of the TomShidi needle and foraminotomy up to 9 mm, with subsequently removal of disk material through the endoscope. Scar size is around 8 mm. CONCLUSION: PTED seems a promising alternative to conventional discectomy in patients with LDH and can be performed safely.

Risk Factors and Management of Incisional Cerebrospinal Fluid Leakage After Craniotomy: A Retrospective International Multicenter Study.

BACKGROUND: Incisional cerebrospinal fluid (iCSF) leakage is a serious complication after intradural cranial surgery. OBJECTIVE: To determine the incidence and risk factors of iCSF leakage after craniotomy. Secondarily, the complications after iCSF leakage and the success rate of iCSF leakage treatment was studied. METHODS: All patients who underwent an intradural cranial surgery from 2017 to 2018 at 5 neurosurgical centers were retrospectively included. Data were retrieved from medical records with 2 months of follow-up. First, univariate regression analyses were performed. Subsequently, identified risk factors were evaluated in a multivariate regression analysis. RESULTS: In total 2310 consecutive patients were included. Total iCSF leakage rate was 7.1% (n = 165). Younger age, male, higher body mass index, smoking, infratentorial surgery, and use of a dural substitute were associated with increased iCSF leakage risk, and use of a sealant reduced that risk. The odds for developing a wound infection and/or meningitis were 15 times higher in patients with iCSF leakage compared with patients without leakage. Initial conservative iCSF leakage treatment failed in 48% of patients. In 80% of cases, external cerebrospinal fluid drainage ceased the iCSF leakage. A total of 32% of patients with iCSF leakage required wound revision surgery. CONCLUSION: iCSF leakage risk increases by younger age, higher body mass index, smoking, infratentorial craniotomy, and dural substitute use, whereas sealant use reduced the risk for iCSF leakage. The leak increases the risk of postoperative infections. When iCSF leakage occurs, immediate external cerebrospinal fluid drainage or wound revision should be considered.

Patient preferences for treatment of lumbar disc herniation: a discrete choice experiment.

OBJECTIVE: Lumbar discectomy is a frequently performed procedure to treat sciatica caused by lumbar disc herniation. Multiple surgical techniques are available, and the popularity of minimally invasive surgical techniques is increasing worldwide. Clinical outcomes between these techniques may not show any substantial differences. As lumbar discectomy is an elective procedure, patients' own preferences play an important role in determining the procedure they will undergo. The aims of the current study were to determine the relative preference weights patients apply to various attributes of lumbar discectomy, determine if patient preferences change after surgery, identify preference heterogeneity for choosing surgery for sciatica, and calculate patient willingness to pay for other attributes. METHODS: A discrete choice experiment (DCE) was conducted among patients with sciatica caused by lumbar disc herniation. A questionnaire was administered to patients before they underwent surgery and to an independent sample of patients who had already undergone surgery. The DCE required patients to choose between two surgical techniques or to opt out from 12 choice sets with alternating characteristic levels: waiting time for surgery, out-of-pocket costs, size of the scar, need of general anesthesia, need for hospitalization, effect on leg pain, and duration of the recovery period. RESULTS: A total of 287 patients were included in the DCE analysis. All attributes, except scar size, had a significant influence on the overall preferences of patients. The effect on leg pain was the most important characteristic in the decision for a surgical procedure (by 44.8%). The potential out-of-pocket costs for the procedure (28.8%), the wait time (12.8%), need for general anesthesia (7.5%), need for hospitalization (4.3%), and the recovery period (1.8%) followed. Preferences were independent of the scores on patient-reported outcome measures and baseline characteristics. Three latent classes could be identified with specific preference patterns. Willingness-to-pay was the highest for effectiveness on leg pain, with patients willing to pay €3133 for a treatment that has a 90% effectiveness instead of 70%. CONCLUSIONS: Effect on leg pain is the most important factor for patients in deciding to undergo surgery for sciatica. Not all proposed advantages of minimally invasive spine surgery (e.g., size of the scar, no need of general anesthesia) are necessarily perceived as advantages by patients. Spine surgeons should propose surgical techniques for sciatica, not only based on own ability and proposed eligibility, but also based on patient preferences as is part of shared decision making.

Single-Arm, Open-Label, Multicenter Study to Evaluate the Safety and Performance of Dura Sealant Patch in Reducing Cerebrospinal Fluid Leakage Following Elective Cranial Surgery: The ENCASE Trial Study Protocol.

BACKGROUND: Cerebrospinal fluid (CSF) leakage is one of the most common neurosurgical complications, occurring in 4% to 32% of surgical cases, with a higher incidence in complicated skull base surgery, intradural spine surgery, and the surgery of the posterior fossa. Our group developed a Dural Sealant Patch (DSP) for watertight dural closure after cranial surgery. OBJECTIVE: To clinically study for the first time the safety and performance of the DSP as a means of reducing CSF leakage in patients undergoing elective cranial intradural surgery with a dural closure procedure. METHODS: We will conduct an open-label, single-arm, multicenter study with a 360 d (12 mo) follow-up. A total of 40 patients will be enrolled at 3 sites. The primary endpoint is a combination of occurrences of one of the following events: postoperative percutaneous CSF leakage, intraoperative leakage at 20 cm H2O, or postoperative wound infection. The secondary endpoints are pseudomeningocele and thickness of dura + DSP. EXPECTED OUTCOMES: Not more than 3 patients will meet the primary endpoint suggesting safety and efficacy. DISCUSSION: As a next step, a randomized controlled trial against the best current practice will follow to evaluate if DSP reduces CSF leakage while its safety is noninferior.

Cognitive functioning in patients with nonfunctioning pituitary adenoma before and after endoscopic endonasal transsphenoidal surgery.

OBJECTIVE: Patients with nonfunctioning pituitary adenomas (NFPAs) can suffer from cognitive dysfunction. However, the literature on longitudinal cognitive follow-up of patients undergoing endoscopic endonasal transsphenoidal surgery (EETS) is limited. This study was performed to investigate perioperative cognitive status and course in patients with NFPAs. METHODS: Patients underwent computerized neuropsychological assessment 1 day before (n = 45) and 3 months after (n = 36) EETS. Performance in 7 domains was measured with a computerized test battery (CNS Vital Signs) and standardized using data from a healthy control group. The authors conducted analyses of cognitive performance at both time points and changes pre- to post-ETSS on a group and an individual level. Linear multiple regression analyses were employed to investigate predictors of cognitive performance. RESULTS: On average, patients scored significantly lower in 6 of 7 cognitive domains before and after surgery than controls. Impairment proportions were significantly higher among patients (56% before surgery, 63% after surgery) than among controls. Patients showed no change over time in group-level (mean) performance, but 28% of individual patients exhibited cognitive improvement and 28% exhibited cognitive decline after surgery. Hormonal deficiency showed a positive correlation with verbal memory before surgery. Postoperative performances in all cognitive domains were predicted by preoperative performances. CONCLUSIONS: Cognitive impairment was present before and after EETS in over half of NFPA patients. Individual patients showed diverse postoperative cognitive courses. Monitoring of cognitive functioning in clinical trajectories and further identification of disease-related and psychological predictors of cognition are warranted.

Simulating Internal Carotid Artery Injury during Transsphenoidal Transclival Endoscopic Surgery in a Perfused Cadaver Model.

Introduction Managing internal carotid artery (ICA) injury during extended endoscopic transsphenoidal surgery is an extreme challenge. We aimed to find a possible surgical treatment strategy. Methods We operated seven fresh, perfused cadaver heads with a transsphenoidal endoscopic approach of the ICA using a three-dimensional-high definition (3D-HD) endoscope. We made a paraclival ICA leak, which we tried to manage with clips and microsutures. Results Accurate transsphenoidal clip application on the ICA was impossible with standard aneurysm clips and applier. It was only feasible with a 9 mm slightly bended clip that could be opened from the inside and be applied with a dedicated flexible thin applier. Transsphenoidal suturing of an ICA leak was impossible from the ipsilateral nostril or with standard microinstruments. Suturing was only feasible from the contralateral nostril using flexible microinstruments with a thin 90-mm shaft. This was technically very challenging and involved a steep learning curve. Conclusion Tamponade with muscle or fat and a quick transfer to the angiography suite for endovascular control remains the preferable option in case of an ICA leak during endoscopic transsphenoidal surgery. If tamponade gives insufficient initial control, ICA clipping could be possible with dedicated instruments, with risk of increasing the defect, stenosis, or occlusion of the vessel. Transsphenoidal ICA suturing remains extremely difficult, and laboratory practice seems essential.