A streamlined protocol for the use of the semi-sitting position in neurosurgery: a report on 48 consecutive procedures

Optimizing the selection of the endoscopically assisted supracerebellar transtentorial approach to the medial temporo-occipital region: Clinical application of one novel grid coordinate system

The endoscopically assisted supracerebellar transtentorial (eSCTT) approach is advocated for managing pathologies of the medial temporo-occipital region, but quantitative analysis is currently lacking. The aims of this study were to establish a grid coordinate system on the tentorium to model the anatomical relationship between medial temporo-occipital region pathology and the slope of the tentorium, and then to compare the paramedian eSCTT and extreme-lateral eSCTT approaches quantitatively. Bilateral paramedian and extreme-lateral eSCTT approaches were used to dissect three adult cadaveric heads anatomically. A grid coordinate system was established on the tentorium, and the angles of attack and depth of the surgical corridor of each coordinate point were obtained so that the two eSCTT approaches could be compared statistically. The measurements were then analyzed to determine the condition for selecting each eSCTT approach, and its clinical feasibility was assessed in three patients with large tumors in the medial temporo-occipital region. For coordinate points where the X-coordinate on the grid coordinate system was 1 cm outside the apex of the tentorium, the paramedian eSCTT approach had a significantly wider angle of attack and shorter depth of surgical corridor than the extreme-lateral eSCTT approach. In contrast, the extreme-lateral eSCTT approach was better for coordinate points where the Y-coordinate on the grid coordinate system was 1 cm in front of the apex of the tentorium. The long axis of each patient's tumor was projected on to the tentorium and its corresponding coordinate points were used to match the more appropriate eSCTT approach. Preliminary results for three patients treated with the eSCTT approach for large tumors in the medial temporo-occipital region were encouraging. When the eSCTT approach is applied to manage a large tumor of the medial temporo-occipital region, assessment of the long axis of the tumor and knowledge of the selective condition for each eSCTT approach can help in clinical decision-making.

Endoscopic-assisted paramedian supracerebellar infratentorial approach to the posterior portion of the third ventricle: anatomical study and surgical cases

BACKGROUND

To date, morphometrical data providing a systematic quantification of accessibility and operability parameters to the boundaries of the posterior portion of the third ventricle (PTV) when applying an endoscopic-assisted paramedian supracerebellar infratentorial approach (EPSIA) are lacking. We performed an anatomical study and complemented our findings with surgical cases.

METHODS

Eight EPSIAs towards the PTV were performed in cadaveric specimens. Optimal approach angles (OA), surgical freedom (SF) and operability indexes (Oi) to the PTV boundaries were assessed. Additionally, a 54-year-old man and 33-year-old woman were operated on PTV tumors applying the EPSIA.

RESULTS

Sagittal OA to ventricle's roof and floor was 36±1.4° and 25.5±3.5° respectively, axial OA to the ipsilateral and contralateral ventricle's wall were 9.5±1.3° and 28.5±1.6°. SF was maximal on the contralateral wall (121.2±19.3mm2), followed by the roof (112.7±18.8mm2), floor (106.6±19.2mm2) and ipsilateral wall (94.1±15.7mm2). SF was significantly lower along the ipsilateral compared the contralateral wall (P<0.01) and roof (P<0.05). Facilitated surgical maneuvers with multiangled exposure were possible up to 8.5±1.07mm anterior to ventricle's entrance, whereas surgical maneuvers were possible but difficult up to 15.25±3.7mm. Visualization of more anterior was possible up to a distance of 27±2.9mm, but surgical maneuvers were barely feasible. EPSIA enabled successful resection of both PTV tumors and postoperative course was uneventful.

CONCLUSIONS

EPSIA can be effective for approaching the PTV, enabling surgery along all boundaries, but especially on its roof and contralateral wall. In the not-enlarged ventricle, surgical maneuvers are feasible up to the level of the Monro foramen, becoming more limited anteriorly.

Postoperative elevated bed header position versus supine in the management of chronic subdural hematoma: a systematic review and meta-analysis

BACKGROUND

Chronic subdural hematoma (CSDH) is a prevalent type of intracranial hemorrhage. Surgical interventions, such as Twist Drill Craniostomy and Burr Hole Craniostomy, are employed for its treatment. However, limited information exists regarding the impact of postoperative head position (supine vs. elevated) on clinical outcomes. We aim to assess whether patients' head position after surgery influences their prognosis.

METHOD

We conducted a PRISMA-compliant systematic review and meta-analysis. Our search encompassed PubMed, Cochrane CENTRAL, Scopus, Web of Science, and Embase databases to identify relevant published studies. Data were meticulously extracted, pooled using a fixed model, and reported as risk ratios (RR) with 95% confidence intervals (CI). Statistical analysis was performed using R and Stata MP v.17.

RESULTS

Five studies involving 284 patients were included in our meta-analysis. We focused on three primary clinical outcomes, comparing the supine and elevated header positions. Notably, there was no statistically significant difference between the supine and elevated positions in terms of recurrence rate (RR 0.77, 95% CI [0.44, 1.37]), second intervention for recurrence (RR 1.07, 95% CI [0.42, 2.78]) and postoperative complications (RR 1.16, 95% CI [0.70, 1.92]).

CONCLUSION

Current studies have proved no difference between supine and elevated bed header positions regarding recurrence rate, second intervention for recurrence, and postoperative complications. Future RCTs with long-term follow-ups are recommended.

Dynamic Lateral Semisitting Position for Supracerebellar Approaches: Technical Note and Case Series

BACKGROUND

It has always been a matter of debate which position is ideal for the supracerebellar approach. The risk of venous air embolism (VAE) is the major deterrent for surgeons and anesthesiologists, despite the fact that sitting and semisitting positions are commonly used in these operations.

OBJECTIVE

To demonstrate a reduction on the risk of VAE and tension pneumocephalus throughout the operation period while taking advantages of the semisitting position.

METHODS

In this study, 11 patients with various diagnoses were operated in our department using the supracerebellar approach in the dynamic lateral semisitting position. We used end-tidal carbon dioxide and arterial blood pressure monitoring to detect venous air embolism.

RESULTS

None of the patients had clinically significant VAE in this study. No tension pneumocephalus or major complications were observed. All the patients were extubated safely after surgery.

CONCLUSION

The ideal position, with which to apply the supracerebellar approach, is still a challenge. In our study, we presented an alternative position that has advantages of the sitting and semisitting positions with a lower risk of venous air embolism.

The parietooccipital interhemispheric transtentorial approach for pineal tumors

Access to the pineal region has always been a challenge for neurosurgeons. The parietooccipital interhemispheric transtentorial approach is a slight variation of the traditional occipital transtentorial approach that provides adequate exposure to the lesions of the pineal region without introducing additional risks. In this study, the modified parietooccipital interhemispheric transtentorial approach is discussed including step-by-step anatomical cadaveric dissections and operative images. 27 adult patients (age > 18) who were operated over a 30-year period (1992-2022) by the senior author (M.N.P.) at two clinics, Marmara University, Department of Neurosurgery, Istanbul, Turkey and Acibadem Mehmet Ali Aydinlar University, Department of Neurosurgery, Istanbul, Turkey were analyzed. Only pineal region tumors were included in the analysis. Falcotentorial meningiomas and vascular lesions including cavernomas were excluded. 5 cadaveric specimens were dissected step by step following the surgical approach. Each step was documented using a Canon EOS 5D Mark II camera with Canon 100 mm Macro Lens. Step by step images of the dissections were presented including comparison with surgical images. Additional illustrations were used to describe the surgical corridor. The surgical corridor is maintained anterior to the parietooccipital sulcus along the medial of the precuneus. No retraction to the calcarine sulcus resulted in no postoperative hemianopsia. The neurovascular structures along the surgical corridor along with the nuances of the tentorium incision and splenium resection are discussed. The parietooccipital interhemispheric transtentorial approach provides a wide and safe corridor for surgical resection of pineal tumors.

Before the Knife: A Detailed Step-by-Step Description of an Optimized Semi-Sitting Position in Posterior Fossa Surgery

BACKGROUND

In an ample armamentarium in neurosurgery, the semi-sitting position has produced debate regarding its benefits and risks. Although the position is apparently intuitive, many have abandoned its use since its initial inception, because of reported complexity and potential complications, leading to impracticality. However, through standardization, it has been shown not only to be safe but to carry with it many advantages, including less risk of secondary neurovascular injuries and better visualization of the surgical field. As with any surgical technical nuance, the semi-sitting position has advantages and disadvantages that must be weighed before the decision is made to adopt it or not, not only in a case-by-case scenario but also from a departmental standpoint. As we attempt to show, the advantages from a standardized approach for the semi-sitting position in experienced institutions may be more than sufficient to significantly outweigh the disadvantages, making it the preferable option for most, although not all, posterior fossa surgical interventions.

METHODS

In the present study, we aim to elaborate a straightforward narrative of the steps before incision, in an attempt to simplify the complexity of the position, alleviating its disadvantages and exponentially concentrating on its benefits. In nearly 100 steps, we carefully describe the points that culminate with the skin incision, initiating the intraoperative part of the procedure. Each step, therefore, is detailed in full, not in an effort to create a strict manual of the semi-sitting position but rather to facilitate understanding and put the technique into effect in a real-life scenario, thus simplifying what some depict as complex and time consuming.

CONCLUSIONS

Although several of the steps described are also relevant and integral parts of other surgical positioning, we intend to create a protocol, in a stepwise fashion, to allow facilitated following, to be easily implemented in departments with different levels of experience. The steps comprise nursing care through to electrophysiologic and anesthesiologic approaches, along with neurosurgical cooperation, making it a team approach, not only to avoid position-related complications but also to optimize preoperative standardization, constructing a safe, efficient, and patient-centered scenario, to set the best possible stage for the next step: the intraoperative part of the intervention.

Analysis of risk factors for venous air embolism in the semisitting position and its impact on outcome in a consecutive series of 740 patients

OBJECTIVE

Routine use of the semisitting position, which offers several advantages, remains a matter of debate. Venous air embolism (VAE) is a potentially serious complication associated with the semisitting position. In this study, the authors aimed to investigate the safety of the semisitting position by analyzing data over a 20-year period.

METHODS

The incidence of VAE and its perioperative management were analyzed retrospectively in a consecutive series of 740 patients who underwent surgery between 1996 and 2016. The occurrence of VAE was defined by detection of bubbles on transthoracic Doppler echocardiography (TTDE) or transesophageal echocardiography (TEE) studies, a decrease of end-tidal CO2 (ETCO2) by 4 mm Hg or more, and/or an unexplained drop in systolic arterial blood pressure (≥ 10 mm Hg). From 1996 until 2013 TTDE was used, and from 2013 on TEE was used. The possible risk factors for VAE and its impact on surgical performance were analyzed.

RESULTS

There were 404 women and 336 men with a mean age at surgery of 49 years (range 1-87 years). Surgery was performed for infratentorial lesions in 709 patients (95.8%), supratentorial lesions in 17 (2.3%), and cervical lesions in 14 (1.9%). The most frequent pathology was vestibular schwannoma. TEE had a higher sensitivity than TTDE. While TEE detected VAE in 40.5% of patients, TTDE had a detection rate of 11.8%. Overall, VAE was detected in 119 patients (16.1%) intraoperatively. In all of these patients, VAE was apparent on TTDE or TEE. Of those, 23 patients also had a decrease of ETCO2, 18 had a drop in blood pressure, and 23 had combined decreases in ETCO2 and blood pressure. VAE was detected in 24% of patients during craniotomy before opening the dura mater, in 67% during tumor resection, and in 9% during wound closure. No risk factors were identified for the occurrence of VAE. Two patients had serious complications due to VAE. Surgical performance in vestibular schwannoma surgery was not affected by the presence of VAE.

CONCLUSIONS

This study shows that the semisitting position is overall safe and that VAE can be managed effectively. Persistent morbidity is very rare. The authors suggest that the semisitting position should continue to have a place in the standard armamentarium of neurological surgery.

A Retrospective Evaluation of the Retrosigmoidal Approach for Petroclival Meningioma Surgery and Prognostic Factors Affecting Clinical Outcome

Introduction

Petroclival meningioma (PCM) remains a major neurosurgical challenge. There are still controversial strategic treatment concepts about surgical approach, the extent of resection, and postoperative radiotherapy. We aimed to evaluate prognostic factors influencing the progression-free survival (PFS) rates of PCM, with a particular focus on the retrosigmoidal approach, the role of the extent of resection, and postoperative radiotherapy.

Methods

Eighty-nine patients with complete follow-up data were included. All patients were operated on via a retrosigmoidal approach, of whom 19 underwent gross total resection (GTR) and 70 underwent subtotal resection (STR). In the subgroups of tumors with infiltration of the cavernous sinus, 41 patients received near total resection (NTR) and 24 STR. Thirty-one patients received postoperative radiotherapy of the residual tumor and 58 were treated with surgery alone. Kaplan–Meier analyses and Cox regression were used to identify significant factors associated with treatment.

Results

GTR (p=0.0107) and postoperative radiotherapy (p=0.014) were associated with significantly improved PFS. Even the subgroup analysis of extended PCM with infiltration of the cavernous sinus (CS) showed an advantage for PFS after near total resection (NTR) (p=0.0017). The additional radiotherapy of the residual tumor in the CS in this subgroup also showed a beneficial effect on PFS (p=0.012).

Conclusion

The extension of surgical resection remains the most important prognostic factor in relation to oncological outcomes. However, the GTR of extended PCM with infiltration of the CS is associated with significant neurological morbidity and requires additional adjuvant therapy concepts. Postoperative radiotherapy is an important element in the treatment of the residual tumor after surgery.

The semisitting position in pediatric neurosurgery: pearls and pitfalls of a 10-year experience

OBJECTIVE

The authors sought to investigate the pearls and pitfalls of using the semisitting position in pediatric neurosurgery, with special focus on related morbidity and surgical practicability.

METHODS

All pediatric cases at a single institution were evaluated retrospectively. Those patients who underwent procedures in the semisitting position between December 2010 and December 2020 were included in the final analysis. Results were compared with all children who underwent surgery in the prone position for posterior fossa lesions within the same time frame.

RESULTS

A total of 42 posterior fossa surgeries were performed in 38 children in the semisitting position between December 2010 and December 2020. The mean patient age at the time of surgery was 8.9 years (range 13 months-18 years). The data of 24 surgeries performed in the prone position in 22 children during the same time frame were analyzed in comparison. Three children (7.9%) were diagnosed with a persistent foramen ovale preoperatively. The surgery was completed in all cases. The incidence of venous air embolism (VAE) was 11.9%. There was no VAE-related hemodynamic instability, infarction, or death. Endoscopic techniques were applied safely in 14 cases (33.3%). Postoperative pneumocephalus occurred significantly more frequently in patients who had undergone procedures in the semisitting position (p < 0.05), but without the need for intervention. During 1 surgery (2.4%), the patient experienced a postoperative skull fracture and epidural bleeding due to the skull clamp application. Clinical status of the patients immediately after surgery was improved or stable in 33 of the 42 surgeries (78.6%) performed in the semisitting position.

CONCLUSIONS

With attentive performance and an experienced surgical team, the semisitting position is a safe option for posterior fossa surgery in the pediatric population. With a comparable complication profile, the semisitting position offers excellent anatomical exposure, which is ideal for the application of endoscopic visualization. Careful skull clamp application and appropriate monitoring are highly recommended.

European position paper on the management of patients with patent foramen ovale. Part II - Decompression sickness, migraine, arterial deoxygenation syndromes and select high-risk clinical conditions

Patent foramen ovale (PFO) is implicated in the pathogenesis of a number of medical conditions but to date only one official position paper related to left circulation thromboembolism has been published. This interdisciplinary paper, prepared with the involvement of eight European scientific societies, reviews the available evidence and proposes a rationale for decision making for other PFO-related clinical conditions. In order to guarantee a strict evidence-based process, we used a modified grading of recommendations, assessment, development, and evaluation (GRADE) methodology. A critical qualitative and quantitative evaluation of diagnostic and therapeutic procedures was performed, including assessment of the risk/benefit ratio. The level of evidence and the strength of the position statements were weighed and graded according to predefined scales. Despite being based on limited and observational or low-certainty randomised data, a number of position statements were made to frame PFO management in different clinical settings, along with suggestions for new research avenues. This interdisciplinary position paper, recognising the low or very low certainty of existing evidence, provides the first approach to several PFO-related clinical scenarios beyond left circulation thromboembolism and strongly stresses the need for fresh high-quality evidence on these topics.

Awake surgery in sitting position for chronic subdural hematoma

BACKGROUND

Chronic subdural hematoma (CSDH) is a common pathology in neurosurgery, especially in the elderly patients, and its incidence is likely to double in the next decade. Considering various features of CSDH and the procedure itself, a sitting position may retain the best characteristics of classic positioning, while offering additional comfort for both the patient and the surgeon. The aim of this study was to describe the technical aspects of this procedure in the sitting position, to evaluate safety and discuss the benefits and shortcomings of this modification.

METHOD

This study included a series of 55 patients surgically treated for CSDH in a sitting position at our department between December 2017 and September 2019, representing all the patients operated on during the study period by a single surgeon. Bilateral hematomas were present in 19 patients. Outcomes, during the 6-month follow-up period, were defined as good (CSDH and symptoms resolved) or poor (lethal outcome or reoccurrence). All complications were noted, with emphasis on pneumocephalus, and complications related to the sitting position: tension pneumocephalus, venous air embolism, and compression nerve injury.

RESULTS

Complications previously associated with the sitting position were not noted. The Glasgow Coma Scale and Markwalder Grading Scale scores improved significantly after the surgery (p < 0.001 and p = 0.018). Complications were noted in 17 patients (30.9%), and included 5 cerebrospinal fluid drainages, 3 hematoma reoccurrences, 2 wound infections, and 9 more single-occurring complications. The in-hospital mortality was 5.4% (3 out of 55 patients), while the overall mortality was 16.4% within the 6-month follow-up period.

CONCLUSIONS

In our series, even the severely ill patients tolerated the position well. No complications associated with the sitting position were noted. Future studies should confirm the safety of this position and evaluate the potential advantages for both the patient and the surgeon.

Estimation of the head elevation angle that causes clinically important venous air embolism in a semi-sitting position for neurosurgery: a retrospective observational study

Introduction:

The benefits of a sitting position for neurosurgery involving the posterior fossa remain controversial. The main concern is the risk of venous air embolism (VAE). A recent study showed that the rate of VAE was higher when the head was elevated to 45° than when it was elevated to 30°. However, the degree of head elevation that causes clinically important VAE is unclear. The purpose of this study was to estimate the head elevation angle at which the probability of VAE is 50% by using EtCO₂ monitoring to detect of VAE.

Methods:

The anesthesia records of 23 patients who underwent neurosurgery in a sitting position were reviewed retrospectively. Intraoperative ventilation was set to maintain EtCO₂ at approximately 38-42 mmHg. The head elevation angle in each case was determined from a photograph taken by the anesthesiologist or brain surgeon. Nineteen of the 23 cases had photographs available that contained a horizontal reference in the background. Seven cases were treated as VAE during the operation. Six of these cases met the criteria for VAE in this study. Data analysis was performed on a total of 18 patients. The angle between the line connecting the hip joint and the shoulder joint and the horizontal reference was obtained by ImageJ software. Logistic regression was performed using the Python programming language to determine the head elevation angle at which the probability of air embolism was 50%.

Results:

The decision boundary in the logistic regression was 35.7°. This head elevation angle was the boundary where the probability of VAE was 50%.

Conclusion:

The angle of head elevation that caused clinically important VAE was estimated to be 35.7°.

Microsurgical techniques for achieving gross total resection of ependymomas of the fourth ventricle

Ependymomas arising from the ventricular surface present a major challenge to achieving a complete operative extirpation when located in the fourth ventricle given the presence of significant adherence to the floor of the same. Overzealous dissection and removal of a tumor from this zone may precipitate potentially catastrophic neurological deficits attributable to cranial nucleopathies and cranial neuropathies. Consequently, the classic neurosurgical teaching has advised attempted gross total resection, leaving adherent residual in the floor of the fourth ventricle, in order to prevent the development of major cranial nucleopathies and cranial neuropathies. Following surgical tumoral extirpation, residual tumor is adjuvantly stereotactically irradiated. Authors have consequently developed novel neurophysiologically guided microsurgical techniques designed to remove adherent tumor from the fourth ventricular floor. These strategies have successfully and consistently facilitated gross total resection and improved clinical outcomes in patients harboring ependymomas of the fourth ventricle. We discuss and evaluate the innovation in microsurgical strategies developed to achieve complete operative extirpation of tumoral adherence to the floor of the fourth ventricle.

Intraoperative venous air embolism in the non-cardiac surgery-the role of perioperative echocardiography in a case series report

Venous air embolism (VAE) is commonly one of the iatrogenic complications associated with divergent high-risk surgeries. In this case-series report, we presented a series of VAE cases in our institute during the last 6 consecutive years. There were total of nine cases suspected to be VAE according the clinical symptom and signs, of which seven cases were definitively diagnosed VAE using transthoracic echocardiography (TTE). We also reported two presumptive cases of paradoxical VAE during hepatectomy in this case series, furthermore, the cause, complications and hazards secondary to paradoxical VAE were discussed as well. All cases had an uneventful recovery from VAE with the assistance of TTE as well as other therapeutic management of VAE, except one neurosurgical patient died from postoperative hemorrhagic stroke per se. Therefore, VAE or paradoxical air embolism can occur during various non-cardiac operations and the significance of perioperative ultrasound should be emphasized in the treatment of VAE.

The impact of transesophageal echocardiography based protocol for management of adults in the sitting position on the incidence of clinically significant venous air embolism

The purpose of the study was to evaluate the impact of transesophageal echocardiography (TEE) – based protocol for management of adults in the sitting position during elective neurosurgical interventions on the incidence of clinically significant venous air embolism (VAE). Material and Methods ― The study involved 155 adult neurosurgery patients (70 in prospective group and 85 in retrospective group). Surgery in both groups was done in the sitting position. In the prospective group TEE-based protocol was used. Retrospective group served as control. The primary endpoint was considered to be a decrease in the frequency of clinically significant VAE in the prospective group in comparison with the retrospective one. In the prospective group, VAE with Tuebingen grade 3-5 was considered clinically significant. The PFO incidence and severity and the effect of the number of episodes of VAE per case on its maximum severity during surgery were also analyzed. Any complication in the postoperative period believed to be associated with the position of the patient on the table during the surgery was recorded. Results ― The incidence of the clinically significant VAE in the retrospective group was 23.5% (95% CI 15-34) and was 16.4% higher than the frequency in the prospective group (chi-square=7.6197, df=1, p=0.005). 50% (95% CI 38-62) of patients in prospective group developed VAE during surgery. In 16 cases, the number of episodes was more than one. The number of episodes of VAE in the observation was reliably associated with the maximum severity of VAE during the observation (Z=4.11; p<0.001). A moderate strength relationship was determined between them (SomersDelta=0.43; 95% CI 0.17-0.7). Not a single case of paradoxical air embolism was detected in a series of observations. None of the patients has got a neurological deficit or cardiopulmonary complications associated with the position on the surgical table in the postoperative period. Pneumocephalus was found in 100% of cases on head computed tomography, which, however, did not need surgical treatment. PFO in the prospective group was detected in 62% (95% CI 52-73) of patients. In 25% (95% CI 16-35), shunting was significant. A large PFO without Valsalva maneuver was detected in 12.5% (95% CI 6-21) of cases. Conclusion ― The use of the TEE-based protocol for the management of adult patients in a sitting position during elective neurosurgical interventions can reduce the incidence of clinically significant VAE.

The Effects of Patient Positioning on the Outcome During Posterior Cranial Fossa and Pineal Region Surgery

Background: Surgery on posterior cranial fossa (PCF) and pineal region (PR) carries the risks of intraoperative trauma to the brainstem structures, blood loss, venous air embolism (VAE), cardiovascular instability, and other complications. Success in surgery, among other factors, depends on selecting the optimal patient position. Our objective was to find associations between patient positioning, incidence of intraoperative complications, neurological recovery, and the extent of surgery.

Methods: This observational study was conducted in two medical centers: The Ohio State University Wexner Medical Center (USA) and The Burdenko Neurosurgical Institute (Russian Federation). Patients were distributed in two groups based on the surgical position: sitting position (SP) or horizontal position (HP). The inclusion criteria were adult patients with space-occupying or vascular lesions requiring an open PCF or PR surgery. Perioperative variables were recorded and summarized using descriptive statistics. The post-treatment survival, functional outcome, and patient satisfaction were assessed at 3 months.

Results: A total of 109 patients were included in the study: 53 in SP and 56 in HP. A higher proportion of patients in the HP patients had >300 mL intraoperative blood loss compared to the SP group (32 vs. 13%; p = 0.0250). Intraoperative VAE was diagnosed in 40% of SP patients vs. 0% in the HP group (p < 0.0001). However, trans-esophageal echocardiographic (TEE) monitoring was more common in the SP group. Intraoperative hypotension was documented in 28% of SP patients compared to 9% in HP group (p = 0.0126). A higher proportion of SP patients experienced a new neurological symptom compared to the HP group (49 vs. 29%; p = 0.0281). The extent of tumor resection, postoperative 3-months survival, functional outcome, and patient satisfaction were not different in the groups.

Conclusions: The SP was associated with, less intraoperative bleeding, increased intraoperative hypotension, VAE, and postoperative neurological deficit. More HP patients experienced macroglossia and increased blood loss. At 3 months, there was no difference of parameters between the two groups.

Clinical Trial Registration:ClinicalTrials.gov: registration number NCT03364283.

Praying Sitting Position for Pineal Region Surgery: An Efficient Variant of a Classic Position in Neurosurgery

BACKGROUND

The sitting position has lost favor among neurosurgeons partly owing to assumptions of increased complications, such as venous air embolisms and hemodynamic disturbances. Moreover, the surgeon must assume a tiring posture. We describe our protocol for the "praying position" for pineal region surgery; this variant may reduce some of the risks of the sitting position, while providing a more ergonomic surgical position.

METHODS

A retrospective review of 56 pineal lesions operated on using the praying position between January 2008 and October 2015 was performed. The praying position is a steeper sitting position with the upper torso and the head bent forward and downward. The patient's head is tilted about 30° making the tentorium almost horizontal, thus providing a good viewing angle. G-suit trousers or elastic bandages around the lower extremities are always used.

RESULTS

Complete lesion removal was achieved in 52 cases; subtotal removal was achieved in 4. Venous air embolism associated with persistent hemodynamic changes was nonexistent in this series. When venous air embolism was suspected, an immediate reaction based on good teamwork was imperative. No cervical spine cord injury or peripheral nerve damage was reported. The microsurgical time was <45 minutes in most of the cases. Postoperative pneumocephalus was detected in all patients, but no case required surgical treatment.

CONCLUSIONS

A protocolized praying position that includes proper teamwork management may provide a simple, fast, and safe approach for proper placement of the patient for pineal region surgery.

The semisitting position: analysis of the risks and surgical outcomes in a contemporary series of 425 adult patients undergoing cranial surgery

OBJECTIVE

The objective of this study was to analyze the incidence of the primary complications related to positioning or surgery and their impact on neurological outcome in a consecutive series of patients undergoing elective surgery in the semisitting position.

METHODS

The authors prospectively collected and retrospectively analyzed data from adult patients undergoing elective surgery in the semisitting position for a cranial disease. Patients were managed perioperatively according to a standard institutional protocol, a standardized stepwise positioning, and surgical maneuvers to decrease the risk of venous air embolism (VAE) and other complications. Intraoperative and postoperative complications were recorded. Neurointensive care unit (NICU) length of stay (LOS) and hospital LOS were the intermediate endpoints. Neurological outcome was the primary endpoint as determined by the modified Rankin scale (mRS) score at 6 months after surgery.

RESULTS

Four hundred twenty-five patients were included in the analysis. VAE occurred in 90 cases (21%) and it made no significant statistical difference in NICU LOS, hospital LOS, and neurological outcome. No complication was directly related to the semisitting position, although 46 patients (11%) experienced at least 1 surgery-related complication and NICU LOS and hospital LOS were significantly prolonged in this group. Neurological outcome was significantly worse for patients with complications (p < 0.0001).

CONCLUSIONS

Even in the presence of intraoperative VAE, the semisitting position was not related to an increased risk of postoperative deficits and can represent a safe additional option for the benefit of specific surgical and patient needs.

Circumferential Reconstruction of Subaxial Cervical and Cervicothoracic Spine by Simultaneously Combined Anterior-posterior Approaches in the Sitting Position

OBJECTIVE

To introduce and analyze the feasibility of a new surgical strategy for circumferential reconstruction of subaxial cervical and cervicothoracic spine by simultaneously combined anterior-posterior approach in the sitting position.

METHODS

A retrospective review was performed for seven patients who underwent the above surgical procedure between July 2011 and January 2015. Among the seven patients, there were six men and one woman, with an average age of 52 years (range, 36-79 years). Six patients were confirmed to have a lower subaxial cervical fracture and dislocation with a locked facet joint, and the other patient had an invasive tumor involving both anterior and posterior parts of vertebrae and lamina, detected by radiological examination. The levels involved for all patients were from C₄ to T₂ . According to American Spinal Injury Association (ASIA) classification, one case was class A, four were class B, and two were class D. The patients were restricted in the sitting position with traction and a halo in extension to immobilize the head during the operation. The simultaneously combined anterior-posterior operation for reduction, decompression or tumor resection and circumferential reconstruction was carried out.

RESULTS

Both anterior and posterior procedures were successfully completed simultaneously in the sitting position in all cases. There were no perioperative complications. The average operative time was 175 ± 32 min (range, 120-240 min), and the mean blood loss was 430 ± 85 mL (range, 200-1100 mL). The patients were followed up for 35.8 months (range, 18-60 months). The symptom of neck pain improved distinctly and no evidence of implant failure was noted in any patients. Neurological status improvement was confirmed in six patients, who had suffered incomplete paralysis. The ASIA grade improved in five patients, and two cases had no change in grade.

CONCLUSIONS

The "sitting position" simultaneously combined anterior-posterior approach is safe and is superior to the traditional prone position and supine position, and the surgical results are satisfactory.

Vascular air embolism: A silent hazard to patient safety

PURPOSE

To narratively review published information on prevention, detection, pathophysiology, and appropriate treatment of vascular air embolism (VAE).

MATERIALS AND METHODS

MEDLINE, SCOPUS, Cochrane Central Register and Google Scholar databases were searched for data published through October 2016. The Manufacturer and User Facility Device Experience (MAUDE) database was queried for "air embolism" reports (years 2011-2016).

RESULTS

VAE may be introduced through disruption in the integrity of the venous circulation that occurs during insertion, maintenance, or removal of intravenous or central venous catheters. VAE impacts pulmonary circulation, respiratory and cardiac function, systemic inflammation and coagulation, often with serious or fatal consequences. When VAE enters arterial circulation, air emboli affect cerebral blood flow and the central nervous system. New medical devices remove air from intravenous infusions. Early recognition and treatment reduce the clinical sequelae of VAE. An organized team approach to treatment including clinical simulation can facilitate preparedness for VAE. The MAUDE database included 416 injuries and 95 fatalities from VAE. Data from the American Society of Anesthesiologists Closed Claims Project showed 100% of claims for VAE resulted in a median payment of $325,000.

CONCLUSIONS

VAE is an important and underappreciated complication of surgery, anesthesia and medical procedures.

Venous air embolism in the sitting position in cranial neurosurgery: incidence and severity according to the used monitoring

BACKGROUND

There is an ongoing debate about the sitting position (SP) in neurosurgical patients. The SP provides a number of advantages as well as severe complications such as commonly concerning venous air embolism (VAE). The best monitoring system for the detection of VAE is still controversial.

METHODS

In this retrospective analysis we compared 208 patients. Transesophageal echocardiography (TEE) or transthoracic Doppler (TTD) were used as monitoring devices to detect VAE; 101 cases were monitored with TEE and 107 with TTD.

RESULTS

The overall incidence of VAE was 23% (TTD: 10%; TEE: 37%), but the incidence of clinically relevant VAE (drop in end-tidal carbon dioxide above 3 mmHg) was higher in the TTD group (9 out of 17 VAE, 53%) compared to the TEE group (19 out of 62 VAE, 31%). None of the patients with recorded VAE had clinically significant sequelae.

CONCLUSIONS

In this small sample we found more VAE events in the TEE group, but the incidence of clinically relevant VAE was rare and comparable to other data. There is no consensus in the definition of clinically relevant VAE.

Simultaneously Combined Anterior-Posterior Approaches for Subaxial Cervical Circumferential Reconstruction in a Sitting Position

The purpose of this article is to introduce and analyze the feasibility of simultaneously combined anterior-posterior approaches for subaxial cervical circumferential reconstruction in sitting position. A retrospective case review was performed for above surgery procedure. A 79-year-old man was confirmed subaxial cervical fracture and dislocation with facet locked by radiological examination, and the involved levels were C5-6. According to American Spinal Injury Association (ASIA) classification, the impairment scale was grade B. And the Subaxial Cervical Spine Injury and Severity Score (SLIC) were 9. The patient was restricted in sitting position with traction on a halo in extension to immobilize the head during the operation. A posterior laminectomy and pedicle screws insertion to the involved cervical spine was performed firstly. And then the anterior discectomy and strut graft were accomplished through an anterior cervical approach. The final fixation was finished by clamping the strut graft with pedicle screw system. Total blood loss was 600 ml and the total operating time was 150 min. The patient was followed up for 6 months. The symptom of neck pain improved distinctly and no evidence about implant failure was noted. Neurological status improvement was confirmed and the ASIA scale was improved to grade C. We believed that the simultaneously combined anterior-posterior approach in sitting position was safe and more advantageous for appropriate cases.

Foramen Magnum Meningioma: Some Anatomical and Surgical Remarks through Five Cases

Study Design

Foramen magnum meningioma foramen magnum meningioma (FMM) represents 2% all of meningiomas. The clinical symptomatology is usually insidious and consists of headache, neck pain and hypoesthesia in C2 dermatome. Because of their location, the management is challenging.

Purpose

The purpose of this paper is to present our experience in the surgery of FMM.

Overview of Literature

Since 1938, numerous series have been published but they are very heterogeneous with high variability of location and surgical approaches.

Methods

During two years, we operated 5 patients with FMM. All the patients had magnetic resonance imaging (MRI) with angio-MRI to study the relationship between tumour and vertebral artery (VA). In all the cases, we used prone position.

Results

In one case, considering the tumour localization (posterior and pure intradural) the tumour was removed via a midline suboccipital approach with craniotomy and C1-C2 laminectomy. In all other cases, meningiomas were posterolateral (classification of George) with extradural extension in one case. In all cases, VA was surrounded by tumor. So, we opted for a modified postero-lateral approach with inverted L incision, craniotomy and C1-C2 laminectomy without resect occipital condyle. Epidural part of VA was identified and mobilized laterally. Once VA was identified we opened dura mater and began to remove the tumour.

Conclusions

In this paper, we present five cases of operated FMM, describe our approaches, the reason of each approach and propose some surgical remarks.

Successful resection of anterior and anterolateral lesions at the craniovertebral junction using a simple posterolateral approach

Tumors at the craniovertebral junction (CVJ) often present a challenge due to proximity to vital neurovascular structures. In the last few decades, many authors have proposed complex surgical approaches to access pathologies located anterior or anterolateral to the CVJ with the hopes of reducing morbidity. We propose that the simple posterolateral approach in a semi-sitting position can be used to resect most anterior and anterolateral CVJ tumors safely and effectively. We retrospectively reviewed the clinical series of 10 patients treated by the senior author using the posterolateral suboccipital approach to treat anterior or anterolateral CVJ pathologies. We describe our surgical techniques, outcomes, and present illustrative patients. Gross total resection was achieved in eight patients (80%). Good functional outcome (Glasgow Outcome Scale 4-5) was obtained in all patients. Preoperative symptoms and deficits were improved (78%) or stable (22%) in all patients. There was one (10%) surgical complication that was cerebrospinal fluid leak requiring reoperation. There was no permanent morbidity or mortality in this series. There were two (20%) medical complications including deep vein thrombosis and pulmonary embolus. There were three (30%) transient neurologic complications, dysphagia in two and dysarthria in one, all of which resolved completely in early follow-up. The majority of anterior or anterolateral CVJ lesions can be successfully removed using the simple posterolateral approach.