The influence of surgical experience on the rate of intraoperative aneurysm rupture and its impact on aneurysm treatment outcome

How Good is Neurosurgical Training? Validation of a Perfused Microsurgical Aneurysm Training Simulator Using a Modified Objective Structured Assessment of Aneurysm Clipping Skills Score and Indocyanine Green Angiography

BACKGROUND AND OBJECTIVES

The training of cerebrovascular neurosurgeons faces significant challenges, particularly due to the decreasing volume of aneurysm clipping procedures. Traditional training methods rely heavily on clinical case availability, which limits skill development. This study aimed to implement and validate a Microsurgical Aneurysm Training Simulator (MATS) that offers a comprehensive, realistic, and cost-effective solution for neurosurgical training.

METHODS

MATS was designed using semiautomated algorithms and additive manufacturing to replicate a bifurcation aneurysm of the middle cerebral artery. The simulator includes a pulsatile perfusion system and is compatible with indocyanine-green angiography. The simulation was evaluated by medical students, residents, and experienced neurosurgeons through face, content, and construct validity assessments. Performance was measured using a modified Objective Structured Assessment of Aneurysm Clipping Skills.

RESULTS

MATS demonstrated high face and content validity, particularly in replicating the visual and procedural aspects of aneurysm clipping. Participants across all experience levels showed significant improvements in modified Objective Structured Assessment of Aneurysm Clipping Skills scores, with medical students displaying the most pronounced learning curve. The simulators compatibility with indocyanine green angiography was confirmed, though limitations were noted in replicating physiological perfusion pressures and the visual impact of subarachnoid hemorrhage during aneurysm rupture simulations.

CONCLUSION

MATS is a validated, cost-effective, and reproducible tool that significantly enhances neurosurgical training by improving technical skills, especially in inexperienced participants. While the simulator effectively mimics key aspects of aneurysm surgery, further research is needed to assess its predictive validity and its potential impact on actual surgical outcomes.

Aneurysmal Subarachnoid Hemorrhage; Early Surgery; Neurosurgeons Experience; Patient Outcome

BACKGROUND

This study examined the impact of neurosurgeons' experience on surgical timing and outcomes in aneurysmal subarachnoid hemorrhage (aSAH) and questioned the adherence to early surgery as recommended by recent guidelines.

METHODS

A retrospective analysis of 196 aSAH patients treated between 2013 and 2020 was conducted. Variables included age, sex, initial Glasgow Coma Scale (GCS) scores, World Federation of Neurological Surgeons grades, Fisher's grades, rebleeding, hydrocephalus, and preoperative-postoperative neurological status. Neurosurgeons' experience was categorized by the number of surgeries performed: >200 (group 1), 101-200 (group 2), and <100 (group 3). Outcomes measured were postoperative neurological deterioration (post-ND), 6-month modified Rankin Scale score, and mortality. Statistical analysis included Pearson's χ2 test, t-test, analysis of variance, and logistic regression, with significance set at P < 0.05.

RESULTS

Of the patients, 50.5% were female, with an average age of 55.1 ± 13.2 years. Early surgery was associated with lower GCS scores and lower surgical experience (GCS odds ratio [OR] 1.405, P = 0.025; experience OR 19.199, P < 0.001). Post-ND rates were 13%, 36.1%, and 21.2% in groups 1, 2, and 3, respectively (P = 0.007). Mortality-related factors included rebleeding (OR 2.625, P = 0.033), neurological deterioration (OR 3.443, P = 0.004), and hydrocephalus (OR 3.408, P = 0.02). Outcomes of Group 1 were found to be superior to the other 2 groups in terms of post-ND (P = 0.007) and hydrocephalus (P = 0.044).

CONCLUSIONS

Experienced neurosurgeons tend to favor delayed intervention for aSAH surgery. While experience positively influences early outcomes, its impact on long-term results is less significant. Future studies could lead to improvements in neurosurgical practices.

Risk factors and outcome analysis of patients with intraoperative rupture (IOR) of ruptured cerebral aneurysm during microsurgical clipping

PURPOSE

To analyse baseline characteristics of patients with intraoperative rupture (IOR) or non-IOR who underwent microsurgical clipping for ruptured intracranial aneurysms. Additionally, to asses functional outcome in terms of Glasgow Outcome Scale (GOS) at 6 and 12 months.

METHODS

A retrospective analysis of 471 patients who underwent microsurgical clipping for ruptured intracranial aneurysms from 2007 to 2018 in Nepal Mediciti Hospital, Nepal. Patients who underwent surgery for unruptured aneurysm were excluded from the study. The association of the base line characteristic in IOR and non-IOR were analysed. Variables analysed were the Hunt and Hess Scale (HHS) dichotomized as (1-3) and (4-5), Modified Fisher Scale dichotomized as (0-2) and (3-4), type of rupture, use of brain retractor, timing of IOR during surgery, aneurysmal factors (size of the neck, location, lobulation) and time of surgery. Outcome, GOS dichotomized into favourable (4-5) and unfavourable (1-3), assessed at 6 months and 12 months.

RESULTS

Out of 471 patients treated for ruptured intracranial aneurysm, IOR occurred in 57 (12.10%) with mean age 49.47 (SD ±12.9), occurred more in smoker than non-smoker (45.6% vs. 18.6%; p=.000) and regular alcohol consumers (36.8% vs. 17.9%; p=.004). Favourable outcome with GOS (4-5) at 6 months was observed among patients with lower HHS (1-3), p=.025 and lower MFS (0-2), p=.04. However, outcome at 12 months was better associated with MFS (p=.013) and aneurysm size (p=.038), with more favourable outcome associated with aneurysm less than 10 mm.

CONCLUSIONS

Alcohol consumption and smoking are associated risk factors that may contribute to IOR. HHS and MFS are strong predictors of outcome for IOR patients at 6 months. However, at 12 months, MFS is more predictive of outcome. Aneurysms greater than 10 mm had a strong association with outcome at 12 months than 6 months.

Focused selection of open cerebrovascular cases for residents interested in cerebrovascular neurosurgery

INTRODUCTION

National and international trends continue to show greater emphasis on endovascular techniques for the treatment of cerebrovascular disease. The cerebrovascular neurosurgeon however must be adequately equipped to treat these patients via both open and endovascular techniques.

METHODS

The decline in open cerebrovascular cases for aneurysm clipping has forced many trainees to pursue open cerebrovascular fellowships to increase case volume. An alternative strategy has been employed at our institution, which is early identification of subspecialty focus with resident driven self-selection of open cerebrovascular cases.

RESULTS

This has allowed recent graduates to obtain enfolded endovascular training and a significant number of open cerebrovascular cases in order to obtain competence and exposure.

DISCUSSION

We advocate for further self-selection paradigms supplemented with simulation training in order to obviate the need for extended post-residency fellowships.

Predictors of Oculomotor Nerve Palsy with Posterior Communicating Aneurysm Clipping in a Surgically Treated Series of 585 Patients: A Single-Center Study

BACKGROUND

Oculomotor nerve palsy (OMNP) is a known risk in surgical management of intracranial aneurysms. The aim of this study was to determine the risk factors for surgery-induced OMNP.

METHODS

This retrospective study examined 585 patients with posterior communicating artery aneurysms treated surgically between January 2000 and July 2019. The patients were categorized into 2 groups according to whether they experienced OMNP. Multiple factors, including sex, age, history of subarachnoid hemorrhage, Hunt and Hess grade, Fisher grade, preoperative time, sizes, sides, number, orientation, intraoperative rupture, and morphology, were analyzed to identify factors associated with surgery-induced OMNP.

RESULTS

The overall OMNP rate was 4.4%. In univariate analysis, large size (P < 0.001), posterior infratentorial projection (P = 0.003), number of subarachnoid hemorrhages (P = 0.005), and late preoperative time (P < 0.001) were associated with increased risk of OMNP. Overall, multivariate logistic regression analysis showed that size (10.1-25 mm: odds ratio [OR] 30.083, P = 0.001, 95% confidence interval [CI], 3.703-244.419; >25 mm: OR 62.179, P = 0.012, 95% CI, 2.402-1609.418), intraoperative rupture (OR 3.018, P = 0.035, 95% CI, 1.083-8.412), and preoperative time (>14 days: OR 10.985, P < 0.001, 95% CI, 3.840-31.428) were independent risk factors of surgery-induced OMNP.

CONCLUSIONS

This study showed that size, intraoperative rupture, and preoperative time were independent predictors of surgery-induced OMNP. Use of advanced technologies during the operation can assist in avoiding this complication.

Initial experience in the microsurgical treatment of ruptured brain aneurysms in the endovascular era: characteristics and safety of the learning curve in the first 300 consecutively treated patients

PURPOSE

Currently, there is an increasing tendency to refer only complex aneurysms for microsurgery. The formation of new neurosurgeons dedicated to open vascular neurosurgery becomes challenging in a situation in which complex aneurysms must be dealt with early in the career, raising questions about the safety of the learning curve.

METHODS

We analyzed the characteristics and surgical results of the first 300 consecutively treated patients after subarachnoid hemorrhage by a single neurosurgeon. The incidence of surgical complications and clinical outcomes during the learning curve were analyzed, looking for critical periods regarding patient safety. Microsurgical operative times were also studied.

RESULTS

A high frequency of wide-necked aneurysms was observed (70.3%), and, as a result, large (> 10 mm), MCA and paraclinoid aneurysms were overrepresented. A statistically significant correlation between surgical experience and clinical outcomes was observed, with progressive surgical experience resulting in a lower incidence of unfavorable outcomes. We also observed a higher frequency of major surgical complications, unfavorable clinical outcomes, and lower complete occlusion rates among the first 40 patients. Microsurgical operative times progressively and significantly decreased during the learning curve.

CONCLUSIONS

We observed a high prevalence of wide-necked aneurysms. Young neurosurgeons must be trained and prepared to deal with these aneurysms early in their careers. Although we observed a decrease in unfavorable results with cumulative surgical experience, the first 40 cases were associated with higher rates of major surgical complications, worse clinical outcomes, and lower complete occlusion rates, indicating that this period may be more critical to patient safety.

Intraoperative Aneurysm Rupture: Surgical Experience and the Rate of Intraoperative Rupture in a Series of 1000 Aneurysms Operated on by a Single Neurosurgeon

OBJECTIVE

This study aims to examine the risk factors that can cause intraoperative rupture (IOR), and especially, the role of surgical experience. To our knowledge, this is the first study to analyze the effect of the surgeon's experience on the IOR rate in 2 different perspectives.

METHODS

A total of 1000 aneurysms in 775 patients were operated on by a single neurosurgeon. The clinical and radiologic data and intraoperative video recordings of all patients were retrospectively analyzed. To evaluate the role of the surgeon's experience on the IOR rate, the aneurysms were divided chronologically into both 5-year periods and each 100 aneurysms. Number, stage, severity, location, management of IORs, and patients' outcomes were determined.

RESULTS

IOR occurred in 55 aneurysms (5.5% per aneurysm). The incidence of IOR decreased gradually in the first 2 groups of 5-year periods (11.4% and 5.9%, respectively). However, in the last 3 groups, the decline remained stable (4%-5%). Considering all groups, this decrease was statistically significant (P = 0.037). When this evaluation was made for each group of 100 aneurysms, similar results were obtained. Mortality also gradually decreased over the years (P = 0.035). Of 8 possible risk factors, rupture status was found to be the only independent predictor for IOR (OR, 8.68; 95% confidence interval, 3.69-20.47; P <0.001).

CONCLUSIONS

Increased surgical experience reduces the IOR rate from 10%-11% to 4%-5% after an average of 250 aneurysm operations. However, this rate does not decrease further with more experience. To our knowledge, a learning curve regarding IOR is presented for the first time in the literature.

Use of Gelatin-thrombin Hemostatic Matrix for Control of Ruptured Cerebral Aneurysm

BACKGROUND

 The use of thrombin-based hemostatic agents (TBHAs) has become common practice in most neurosurgical procedures, both cranial and spinal.

METHODS

 We present the case of a 40-year-old woman who was referred to our institution with intense headache and Fisher grade 3 subarachnoid hemorrhage (SAH) mainly at the level of the right sylvian fissure, caused by a 5.71-mm right middle cerebral artery (MCA) bifurcation aneurysm, with hourglass morphology and a bleb on the bottom. Cerebral angiography demonstrated aneurysm enlargement, compared with the prior angiographic computerized tomography scan.

RESULTS

 A right pterional craniotomy was performed. After initial arachnoid dissection to get proximal vascular control, but before we obtained it, we witnessed profuse bleeding from the aneurysm. Floseal, a gelatin-thrombin matrix sealant, was sprayed over the breach of the aneurysm, and cottonoids were gently pressed with a self-retaining spatula, stopping the hemorrhage. After that, we obtained proximal control with an extradural clinoidectomy and temporary clipping of the right internal carotid artery (ICA) and MCA. Finally, aneurysm dissection and final clipping were performed with the application of two clips. The postoperative course was uneventful, and the patient was discharged on postoperative day 10.

CONCLUSION

 Intraoperative aneurysm rupture (IAR) is a dangerous event that carries great risks-even death. Proper use of TBHAs is a useful and safe way to stop the bleeding, take a deep breath, and achieve proximal vascular control. To the best of our knowledge, this is the first report of the use of TBHA during aneurysm clipping.

Predictors of Intraoperative Aneurysm Rupture, Aneurysm Remnant, and Brain Ischemia following Microsurgical Clipping of Intracranial Aneurysms: Single-Center, Retrospective Cohort Study

BACKGROUND AND STUDY AIMS

 Complete microsurgical clip occlusion of an aneurysm is one of the most important challenges in cerebrovascular surgery. Incorrect position of clip blades as well as intraoperative aneurysm rupture can expose the patient to serious complications such as rebleeding in case of aneurysm remnant and cerebral ischemia in case of occlusion of branching arteries or perforators. The aim of this study was to identify independent predictors of surgery-derived complications (aneurysm remnant and brain ischemia) as well as intraoperative aneurysm rupture in an institutional series of patients.

MATERIAL AND METHODS

 This is a single-institution, retrospective cohort study including 147 patients with 162 aneurysms that were selected for microsurgical clipping due to intracranial aneurysm in a 5-year period. Bivariate and multivariate analyses were performed to identify independent predictors among demographic, clinical, and radiographic factors.

RESULTS

 Increasing aneurysm size with a cutoff value at 9 mm (p = 0.009; odds ratio [OR]: 0.644) and irregular dome shape (p = 0.003; OR: 4.242) were independently associated with brain ischemia and aneurysm remnants that occurred in 13.6 and 17.3% of patients in our group, respectively. Intraoperative rupture was encountered in 27% of patients and its predictors were patient's age (p = 0.002; OR: 1.073) and increasing aneurysm size with a cutoff value at 7 mm (p = 0.003; OR: 1.205).

CONCLUSION

 Aneurysm size, patient's age, and irregular dome shape were the most important risk factors of aneurysm remnant, brain ischemia, and intraoperative aneurysm rupture in our series of patients. We were not able to define a cutoff value for patient's age, but our results showed that with increasing age the risk of intraoperative aneurysm rupture increased.

Major intraoperative aneurysm rupture may increase the risk of cerebral infarction following surgical clipping of unruptured intracranial aneurysms

OBJECTIVE

Intraoperative aneurysm rupture (IAR) could cause a poor outcome. This study aimed to investigate the relationship between IARs and postoperative cerebral infarctions (CIs).

METHOD

We retrospectively reviewed patients with asymptomatic unruptured intracranial aneurysms (UIAs) who received microsurgical clipping in two neurosurgical centers from January 2016 to June 2019. A propensity score matching was done to constitute a cohort. The data were collected regarding the clinical and radiological characteristics. The CI at 1-2 weeks and the functional outcome at two weeks after clipping were recorded. Differences between IAR patients with CIs and without CIs were compared. The relationship between the IARs and postoperative CIs was investigated by using logistic regression analysis.

RESULTS

This study yielded 96 UIAs patients, including 48 patients undergoing IARs and 48 patients not. Twenty patients with CIs at 1-2 weeks after clipping were identified. The rate of CIs in patients undergoing IARs was higher than that in patients not undergoing IARs (OR, 2.88; p = 0.038); moreover, the mRS was also worse in patients undergoing IARs (OR, 1.58; p = 0.015). For patients undergoing IARs, the significance was found in ischemic cerebrovascular disease (OR, 6.40; p = 0.048), Essen stroke risk score (OR, 2.14; p = 0.026), and severity of intraoperative rupture (OR, 5.63; p = 0.023). The multivariate logistic analysis demonstrated the major IARs (OR, 6.09; CI, 1.18-31.53; p = 0.031) as the independent risk factor related to postoperative CI.

CONCLUSION

IARs could increase the risk of postoperative CIs and worsen the functional outcome, and major IAR was the independent risk factor related to the postoperative CIs.

Adverse intraoperative events during surgical repair of ruptured cerebral aneurysms: a systematic review

Compared with endovascular techniques, clipping of ruptured cerebral aneurysms has been shown to associate with increased morbidity in several studies. Despite this, clipping remains the preferred option for many aneurysms. The objective of this study is to describe the reported adverse events of open repair of ruptured cerebral aneurysms and their impact on patient outcome. The PubMed, Embase and Cochrane databases were searched between June 1999 and June 2019 to identify original studies of at least 100 patients undergoing surgical repair of ruptured cerebral aneurysms and in which adverse event rates were reported. Thirty-six studies reporting adverse events in a total of 12,410 operations for repair of ruptured cerebral aneurysms were included. Surgical adverse events were common with 36 event types reported including intraoperative rupture (median rate of 16.6%), arterial injury (median rate of 3.8%) and brain swelling (median rate 5.6%). Only 6 surgical events were statistically shown to associate with poor outcomes by any author and for intraoperative rupture (the most frequently analysed), there was an even split between authors finding a statistical association with poor outcome and those finding no association. Even with modern surgical techniques, the technical demands of surgical aneurysm repair continue to lead to a high rate of intraoperative adverse events. Despite this, it is not known which of these intraoperative events are the most important contributors to the poor outcomes often seen in these patients. More research directed towards identifying the events that most drive operative morbidity has the potential to improve outcomes for these patients.

Surgical Training for the Management of Intraoperative Aneurysm Rupture Using a Three-Dimensional Artificial Model

Background

Intraoperative aneurysm rupture (IAR) is one of the most dreaded complications of microsurgical cerebral aneurysm clipping. The surgical result is directly affected by whether an operator can control IAR. However, the development of endovascular treatment has decreased the probability of exposure to this situation for neurosurgical residents. Therefore, neurovascular surgeons must develop the skills and mental attitude to deal with IAR through off-the-job training, without conducting actual operations.

Materials and Methods

We have developed a tabletop training system using three-dimensional artificial modeling that can be used for daily clinical practice.

Results and Conclusions

Our model is useful for training because of its low cost, reusability, and ease of preparation and practice.

Intraoperative Aneurysm Rupture During Microsurgical Clipping: Risk Re-evaluation in the Post-International Subarachnoid Aneurysm Trial Era

OBJECTIVES

Intraoperative aneurysm rupture (IOAR) is a common complication during intracranial aneurysm (IA) surgery. In light of the paradigm shift regarding IA selected for clipping in the post-International Subarachnoid Aneurysm Trial (ISAT) era, we aimed to evaluate the risk factors and effects of IOAR in an institutional series of clipped ruptured IA (RIA) and unruptured IA (UIA).

MATERIAL AND METHODS

All IAs treated with microsurgical clipping at our institution between 2003 and 2016 were eligible for this study. Demographic, clinical, and radiographic factors were correlated with occurrence of IOAR in univariate and multivariate analyses. The effect on outcome was analyzed for RIA and UIA separately.

RESULTS

Nine hundred and three clipped IAs were included in the final analysis (538 UIA and 365 RIA). IOAR occurred in 163 cases (18.1%), mostly during clipping of RIA (37.5% vs. 4.8%) In multivariate analysis, ruptured status (adjusted odds ratio [aOR], 10.46; P < 0.001), sack size (aOR, 1.05 per mm increase; P = 0.038) and IA location in the anterior communicating artery (aOR, 2.31; P < 0.001) independently predicted IOAR. For RIA cases, IOAR was also independently predicted by rebleeding before therapy (aOR, 3.11; P = 0.033) and clinical severity of subarachnoid hemorrhage (aOR, 1.18 per WFNS grade increase; P = 0.049). IOAR independently predicted poor outcome (aOR, 1.83; P = 0.042) after RIA surgery. In turn, IOAR affected only the risk for cerebral infarct (OR, 3.75; P = 0.003) and incomplete IA occlusion (OR, 3.45; P = 0.003) for UIA cases, but not the outcome (P = 0.263).

CONCLUSIONS

IOAR was independently predicted by the ruptured status, location, and size of IA and by initial severity of aneurysmal bleeding and pretreatment rebleeding. The influence of IOAR differed between RIA and UIA cases.

Monitoring Dynamic Morphological Changes With Electrocardiography-Gated Dynamic 4-Dimensional Computed Tomography Angiography to Predict Intraoperative Rupture of Intracranial Aneurysms

OBJECTIVE

This study aims to evaluate dynamic morphological changes of intracranial aneurysms to predict intraoperative aneurysm rupture (IAR) during clipping.

METHODS

Included in this study were 153 patients, who had ruptured and microsurgical-clipped aneurysms. All patients underwent dual-source computed tomography examination of electrocardiography-gated dynamic 4-dimensional computed tomography angiography before clipping. Original scanning data were reconstructed to produce 20 data sets of cardiac cycles with 5% time intervals. The aneurysm neck, transverse and longitudinal diameters, and volume from the 20 groups of images were measured to calculate their respective change rates. In addition, other data and clinical characteristics were recorded. Data were analyzed by logistic regression to identify factors associated with IAR.

RESULTS

Of the 153 patients, 24 patients experienced IAR. Multivariable analysis revealed that the aneurysm neck change rate (P = 0.0001; odds ratio, 1.276) and aspect ratio (height/neck ratio, P = 0.025; odds ratio, 2.387) are predictors for IAR. When the change rate was greater than or equal to 60%, and the sensitivity and specificity were 91.7% and 76.7%, respectively.

CONCLUSIONS

Aneurysm neck change rate is independent predictor of IAR.

Intraoperative rupture in the surgical treatment of patients with intracranial aneurysms

Intraoperative rerupture (IOR) during clipping of cerebral aneurysms is a difficult complication of microneurosurgery. The aim of this study was to evaluate the incidence of IOR and analyze the strategies for controlling profound hemorrhage. A total of 165 patients with unruptured intracranial aneurysms and 46 patients with subarachnoid hemorrhage (SAH) treated surgically between April 2010 and March 2011, were reviewed. The data were collected with regard to age, sex, presence of symptoms, confounding factors and strategy for controlling intraoperative hemorrhage was analyzed in terms of location of aneurysms, timing of rupture and severity of IOR. 211 patients with 228 aneurysms were treated in this series. There were a total of six IORs which represented an IOR rate of 2.84% per patient and 2.63% per aneurysm. The highest ruptures rates occurred in patients with internal carotid artery aneurysms (25%). Surgeries in the group with ruptured aneurysms had a much higher rate of IOR compared with surgeries in the group with unruptured aneurysms. Of the six IOR aneurysms, one occurred during predissection, four during microdissection and one during clipping. One was major IOR, three were moderate and two were minor. Intraoperative rupture of an intracranial aneurysm can be potentially devastating in vascular neurosurgery. Aneurysm location, presence of SAH and surgical experience of the operating surgeon seem to be important factors affecting the incidence of IOR.

The Impact of Surgical Experience on Major Intraoperative Aneurysm Rupture and Their Consequences on Outcome: A Multivariate Analysis of 538 Microsurgical Clipping Cases

The incidence and associated mortality of major intraoperative rupture (MIOR) in intracranial aneurysm surgery is diverse. One possible reason is that many studies failed to consider and properly adjust the factor of surgical experience in the context. We conducted this study to clarify the role of surgical experience on MIOR and associated outcome. 538 consecutive intracranial aneurysm surgeries performed on 501 patients were enrolled in this study. Various potential predictors of MIOR were evaluated with stratified analysis and multivariate logistic regression. The impact of surgical experience and MIOR on outcome was further studied in a logistic regression model with adjustment of each other. The outcome was evaluated using the Glasgow Outcome Scale one year after the surgery. Surgical experience and preoperative Glasgow Coma Scale (GCS) were identified as independent predictors of MIOR. Experienced neurovascular surgeons encountered fewer cases of MIOR compared to novice neurosurgeons (MIOR, 18/225, 8.0% vs. 50/313, 16.0%, P = 0.009). Inexperience and MIOR were both associated with a worse outcome. Compared to experienced neurovascular surgeons, inexperienced neurosurgeons had a 1.90-fold risk of poor outcome. On the other hand, MIOR resulted in a 3.21-fold risk of unfavorable outcome compared to those without it. Those MIOR cases managed by experienced neurovascular surgeons had a better prognosis compared with those managed by inexperienced neurosurgeons (poor outcome, 4/18, 22% vs. 30/50, 60%, P = 0.013).

Influence of cumulative surgical experience on the outcome of poor-grade patients with ruptured intracranial aneurysm

BACKGROUND

The expansion of endovascular techniques for intracranial aneurysms has led to a global decrease in vascular neurosurgery activity. This situation might impact neurosurgeons' level of expertise, even though they all might have to deal with this surgically challenging pathology. In that context, we wanted to assess the impact of cumulative surgical experience on the outcome of patients with poor-grade subarachnoid haemorrhage (SAH) and intracerebral haemorrhage (ICH) treated by microsurgery.

METHODS

Sixty-seven patients who underwent surgery for a ruptured aneurysm with SAH and ICH, and a WFNS scale of IV/V, were included. Surgeries were performed by five surgeons, whose experience was judged by the total number of aneurysm surgeries performed. The outcome was assessed by three indicators: intraoperative rupture (IOR), early mortality, and the modified Rankin Scale at last follow-up. The time of IOR was reported on an IOR score. The correlation between surgical experience and outcome was assessed by linear regression. Nonlinear regression was used to assess the correlation of the data with a learning curve model.

RESULTS

The analysis showed an influence of surgical experience on intraoperative rupture, with no effect on long-term outcome. No influence was found on early mortality. Increased surgical experience seems to reduce IOR during aneurysm dissection and clip repositioning. Intraoperative rupture data fit Wright's learning curve model.

CONCLUSION

This study suggests a direct impact of cumulative experience on the course of ruptured aneurysm surgery and pleads for the use of training and simulation programmes dedicated to neurovascular surgery.

Caseload as a factor for outcome in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

Object

Increasing evidence exists that treatment of complex medical conditions in high-volume centers is found to improve outcome. Patients with subarachnoid hemorrhage (SAH), a complex disease, probably also benefit from treatment at a high-volume center. The authors aimed to determine, based on published literature, whether a higher hospital caseload is associated with improved outcomes of patients undergoing treatment after aneurysmal subarachnoid hemorrhage.

Methods

The authors identified studies from MEDLINE, Embase, and the Cochrane Library up to September 28, 2012, that evaluated outcome in high-volume versus low-volume centers in patients with SAH who were treated by either clipping or endovascular coiling. No language restrictions were set. The compared outcome measure was in-hospital mortality. Mortality in studies was pooled in a random effects meta-analysis. Study quality was reported according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria.

Results

Four articles were included in this analysis, representing 36,600 patients. The quality of studies was graded low in 3 and very low in 1. Meta-analysis using a random effects model showed a decrease in hospital mortality (OR 0.77 [95% CI 0.60–0.97]; p = 0.00; I2 = 91%) in high-volume hospitals treating SAH patients. Sensitivity analysis revealed the relative weight of the 1 low-quality study. Removal of the study with very low quality increased the effect size of the meta-analysis to an OR of 0.68 (95% CI 0.56–0.84; p = 0.00; I2 = 86%). The definition of hospital volume differed among studies. Cutoffs and dichotomizations were used as well as division in quartiles. In 1 study, low volume was defined as 9 or fewer patients yearly, whereas in another it was defined as fewer than 30 patients yearly. Similarly, 1 study defined high volume as more than 20 patients annually, and another defined it as more than 50 patients a year. For comparability between studies, recalculation was done with dichotomized data if available. Cross et al., 2003 (low volume ≤ 18, high volume ≥ 19) and Johnston, 2000 (low volume ≤ 31, high volume ≥ 32) provided core data for recalculation. The overall results of this analysis revealed an OR of 0.85 (95% CI 0.72–0.99; p = 0.00; I2 = 87%).

Conclusions

Despite the shortcomings of this study, the mortality rate was lower in hospitals with a larger caseload. Limitations of the meta-analysis are the not uniform cutoff values and uncertainty about case mix.

Analysis of the relationship between different bleeding positions on intraoperative rupture anterior circulation aneurysm and surgical treatment outcome

BACKGROUND

It is well recognized that intraoperative aneurysm rupture (IAR) is a serious event that is difficult to manage and has a relatively serious influence on a patient's prognosis. The aim of this study was to evaluate the prognostic value of different bleeding positions of IAR in patients, and to describe the technique that the authors have used to clip the ruptured aneurysms.

METHODS

From May 2009 to March 2012, a total of 148 aneurysms in 135 consecutive patients in our institution underwent clipping surgeries, and 31 IARs occurred in 30 patients. The clinical data of all patients were retrospectively analyzed. Statistics analysis was performed to analyze possible factors of different bleeding positions of IARs, to assist observation.

RESULTS

Outcome was estimated by Glasgow outcome scale via following up or calling back within 1, 3, and 6 months after surgery: 94 patients were 5', 23 patients were 4', nine patients were 3', two patients were 2' and eight patients were 1'. There was no significant difference between the outcome of IAR and that of no intraoperative aneurysm rupture (NIAR) in Hunt-Hess groups 0-III (P = 0.802) and Hunt-Hess groups IV-V (P = 0.229), and the different bleeding positions were shown to be an important factor that significantly influences the patients' prognosis (P = 0.001).

CONCLUSIONS

Different bleeding positions of IAR have a significant impact on surgical outcome; IAR of the neck is the most devastating complication. If surgeons take appropriate measures according to different bleeding positions, the efficiency, accuracy and security of the operation will be improved.

Does the impact of elective temporary clipping on intraoperative rupture really influence neurological outcome after surgery for ruptured anterior circulation aneurysms?--A prospective multivariate study

BACKGROUND

Elective temporary clipping (ETC) is increasingly used in surgery for aneurysms. This study was to assess whether the impact of ETC on intraoperative aneurysmal rupture (IAR) translates into neurological outcome.

METHODS

Patients who underwent surgery for ruptured anterior circulation aneurysms were prospectively studied for various factors related to ETC, IAR and neurological outcome at 3 months. Univariate and multivariate analyses were performed using SPSS20.

RESULTS

Of the total 273 ruptured aneurysm surgeries studied, IAR was observed in only six out of 132 aneurysms (4.5 %) who had ETC, compared with 78 out of 141 (55.3 %) without ETC (p < 0.001). Aneurysms complicated by IAR had significantly longer clipping time (8.3 min) compared with those without IAR (1.9 min) (p < 0.001). IAR had significant association with unfavorable outcome (38 % vs. 24 %) (p = 0.02). Patients with ETC had significantly shorter clipping time (2.9 min) compared with those without ETC (4.8 min) (p = 0.02). Unfavorable outcome was noted in 30 out of 132 with ETC (23 %), compared with 48 out of 141 without ETC (34 %) (p = 0.04). This beneficial effect was nonsignificantly greater in younger and good clinical grade patients. While episodes of ETC within clipping time of 20 min did not show significant difference in outcome, repeated rescue clipping (45 % unfavorable outcome, p = 0.048) and total clipping time of at least 20 min (75 % unfavorable outcome, p = 0.008) had significant impact on outcome. In multivariate analysis, the use of ETC (p = 0.027) and total temporary clipping less than 20 min (p = 0.049) were noted to result in significantly better outcome, independent of other factors.

CONCLUSIONS

The use of ETC decreased the occurrence of IAR and the total clipping time, thereby leading to significantly better outcome, independent of other factors. While repeated elective clipping within total clipping time of 20 min did not influence outcome, repeated rescue clipping and total clipping time of at least 20 min had significant impact on outcome.

Cotton-clipping technique to repair intraoperative aneurysm neck tear: a technical note

BACKGROUND

Intraoperative rupture of an intracranial aneurysm is a potentially devastating but avoidable and manageable complication of aneurysm surgery.

OBJECTIVE

To describe a surgical technique that the authors have used successfully to repair a tear at the neck of an intracranial aneurysm, as well as alternative options for managing this intraoperative complication.

METHODS

The tear on the neck of the aneurysm is covered with a small piece of free cotton and held in place with a suction device to clear the field of blood. The cotton is then clipped onto the tear with an aneurysm clip, using the cotton as a bolster to obliterate the tear. The cotton increases the surface area, allowing the clip to be placed more distally on the neck to preserve patency of the parent artery. Case examples are used to illustrate the technique.

RESULTS

Both authors independently have used this technique on several occasions to successfully repair tears at the neck of an aneurysm.

CONCLUSION

Intraoperative rupture of an intracranial aneurysm is a potentially devastating complication, particularly if a tear occurs at the neck. This simple yet effective method has been very useful in repairing a partial avulsion or tear of the neck of an aneurysm.

Lessons learned by personal failures in aneurysm surgery: what went wrong, and why?

PURPOSE

To analyse the intraoperative complications of a single neurosurgeon, with emphasis on devastating intraoperative incidents, and how they possibly could have been avoided.

METHODS

All the patients operated upon by the author between 1986 and 2002, i.e. 252 patients with 270 craniotomies for 294 aneurysms, were included. All intraoperative events that possibly could have influenced the clinical outcome were recorded prospectively.

RESULTS

A total of 16 cases (6.3% of all the patients) with serious intraoperative incidents were identified. In 11 cases (3.6% of all aneurysms), an intraoperative rupture occurred that was judged to have had mild to severe consequences for the patient. In another four patients (1.6% of all patients), all with unruptured, large aneurysms (>15 mm) of the carotid or middle cerebral arteries, a major vessel occlusion occurred inadvertently. In one patient with a large, unruptured MCA aneurysm, a clip slipped after the closure of the wound, causing a fatal intracerebral haemorrhage. These events had a severe impact on the clinical outcome. In retrospect, most of these incidents could, and should have, been avoided.

CONCLUSIONS

It is recommended to start the training of new aneurysm surgeons on patients with small, supratentorial, unruptured aneurysms, followed by ruptured aneurysms in all other supratentorial locations than the anterior communicating artery (ACOM), which is the supratentorial location that should be the last step in the training of independent aneurysm surgeons.

Blood blister-like aneurysms of the internal carotid artery trunk causing subarachnoid hemorrhage: treatment and outcome

OBJECT

The object of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery (ICA) trunk.

METHODS

The authors performed a single-center, retrospective study. Data analyzed were patient age, sex, Hunt and Hess grade, Fisher grade, time from SAH to hospitalization, aneurysm size and location, collateral capacity of the circle of Willis, time from hospitalization to aneurysm repair, type of aneurysm repair, complications, and Glasgow Outcome Scale (GOS) score at follow-up.

RESULTS

A total of 211 patients suffered SAH from ICA aneurysms. Of these, 14 patients (6.6%) had ICA trunk BBAs; 6 men and 8 women. The median age was 47.8 years (range 29.9-67.7 years). The Hunt and Hess grade was IV or V in 7 cases, and SAH was Fisher Grade 3 + 4 in 6. All aneurysms were small (< 1 cm), without relation to vessel bifurcations, and usually located anteromedially on the ICA trunk. Three patients were treated with coil placement and 11 with clip placement. Of the 7 patients in whom the ICA was preserved, only 1 had poor outcome (GOS Score 2). In contrast, cerebral infarcts developed in all patients treated with ICA sacrifice, directly postoperatively in 2 and after delay in 5. Six patients died, 1 survived in poor condition (GOS Score 3; p < 0.001).

CONCLUSIONS

Internal carotid BBAs are rare, small, and difficult to treat endovascularly, with only 2 of 14 patients successfully treated with coil placement. The BBAs rupture easily during surgery (ruptured in 6 of 11 surgical cases). Intraoperative aneurysm rupture invariably led to ICA trap ligation. Sacrifice of the ICA within 48 hours of an SAH led to very poor outcome, even in patients with adequate collateral capacity on preoperative angiograms, probably because of vasospasm-induced compromise of the cerebral collaterals.

Uncommon presentation of ruptured intracranial aneurysm during surgical evacuation of chronic subdural hematoma: case report

BACKGROUND

There are many factors that predispose an aneurysm to rupture, but there are few real, demonstrable causes that lead to rupture of the aneurysmal sac with a precise cause-effect mechanism.

CASE DESCRIPTION

We report a 74-year-old male patient with chronic subdural hematoma after head trauma, who underwent surgery for evacuation of the hematoma. During surgery, there was sudden copious loss of blood from the drainage tubes that were positioned subdurally. Immediate cerebral computed tomography scan and angiography revealed a subarachnoid hemorrhage at the level of the basal cisterns from a ruptured basilar apex aneurysm. We discuss the cause-effect relationship between the surgery with its positioning of subdural drains and the rupture of a previously unrecognized cerebral aneurysm.

CONCLUSIONS

The rupture of an unknown, previous "unruptured" aneurysm after craniotomy with subdural positioning of drainage, must be considered a possible complication.

Can a “novice” do aneurysm surgery? Surgical outcomes in a low-volume, non-subspecialised neurosurgical unit

The objective of this paper is to review the results of a junior general neurosurgeon performing aneurysm surgery and compare these to the remainder of his low-volume unit. Prospectively collected data was analysed for 114 aneurysms clipped in 99 patients between July 2001 and May 2005. Overall there was a 0.9% mortality rate and 10.8% complication rate. The favourable outcome rate for the unit was 100% for unruptured aneurysms, 90.4% for grades 1-3 patients and 30% for poor grade patients (grades 4 and 5). The novice neurosurgeon had no mortality and a favourable outcome rate of 94.7% for grades 1-3 patients and 50% for poor grade patients. Acceptable results can be obtained with cerebral aneurysm surgery in a low-volume centre by Australian-trained, non-subspecialty neurosurgeons.

A systematic review of the impact of volume of surgery and specialization on patient outcome

BACKGROUND AND METHODS

Volume of surgery and specialization may affect patient outcome. Articles examining the effects of one or more of three variables (hospital volume of surgery, surgeon volume and specialization) on outcome (measured by length of hospital stay, mortality and complication rate) were analysed. Reviews, opinion articles and observational studies were excluded. The methodological quality of each study was assessed, a correlation between the variables analysed and the outcome accepted if it was significant.

RESULTS

The search identified 55,391 articles published between 1957 and 2002; 1075 were relevant to the study, of which 163 (9,904,850 patients) fulfilled the entry criteria. These 163 examined 42 different surgical procedures, spanning 13 surgical specialities. None were randomized and 40 investigated more than one variable. Hospital volume was reported in 127 studies; high-volume hospitals had significantly better outcomes in 74.2 per cent of studies, but this effect was limited in prospective studies (40 per cent). Surgeon volume was reported in 58 studies; high-volume surgeons had significantly better outcomes in 74 per cent of studies. Specialization was reported in 22 studies; specialist surgeons had significantly better outcomes than general surgeons in 91 per cent of studies. The benefit of high surgeon volume and specialization varied in magnitude between specialities.

CONCLUSION

High surgeon volume and specialization are associated with improved patient outcome, while high hospital volume is of limited benefit.

A POPULATION-BASED STUDY OF NEUROSURGICAL AND ENDOVASCULAR TREATMENT OF RUPTURED, INTRACRANIAL ANEURYSMS IN A SMALL NEUROSURGICAL UNIT

OBJECTIVE

Since the introduction of endovascular embolization, the optimal treatment of ruptured aneurysms has been debated. Much of this debate has been based on results from large neurovascular centers and may not be applicable to small neurosurgical centers with low annual aneurysm loads. We think that the results of small centers, such as ours, may also be of some interest.

METHODS

This study included 286 patients treated endovascularly or operated on by the senior investigator (KW) before November 2004. They all had an angiographically verified aneurysm as the source of bleeding in the subarachnoid hemorrhage. Variables related to presentation, radiological findings, treatment, and outcome were recorded.

RESULTS

A significantly higher proportion (66.3%) of the endovascular patients had complete or near-complete recovery (Glasgow Outcome Scale 5) compared with the surgically treated patients (47.8%). When clinical outcomes were dichotomized into favorable (Glasgow Outcome Scale 4–5) and unfavorable (Glasgow Outcome Scale 1–3), no difference was found between the two treatment groups. Treatment-related mortality or morbidity was equal. Significantly more patients were converted from endovascular to surgical treatment than vice versa. No surgically treated patients rebled, whereas four endovascular patients rebled from their previously treated aneurysm.

CONCLUSION

At present in our hospital, the endovascular modality seems to yield a better clinical outcome than surgery and has become our treatment of choice. With increasing use and further refinement of the endovascular techniques, the difference in outcomes between the treatment modalities will probably change even further in favor of the endovascular technique.

Is there a "July phenomenon" in pediatric neurosurgery at teaching hospitals?

OBJECT

Concern for patient safety, among other reasons, recently prompted sweeping changes in resident work policies in the US. Some have speculated that the arrival of new interns and residents at teaching hospitals each July might cause an annual transient increase in poor patient outcomes and inefficient care.

METHODS

Data were analyzed for 4323 craniotomies for tumor resection and 22,072 shunt operations performed in pediatric patients between 1988 and 2000 in US nonfederal hospitals (Nationwide Inpatient Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality, Rockville, MD). In-hospital mortality rates, discharge outcome, complications, and efficiency measures (length of stay [LOS] and hospital charges) for patients treated in July and August were compared with similar data for patients in other months. There were no significant increases in any adverse end point for either tumor or shunt operations in July and August. Odds ratios (95% confidence interval [CI]) for outcome of tumor craniotomies performed in July and August compared with outcome for tumor craniotomies performed in other months were as follows: for mortality rate, 0.43 (0.14-1.32); for adverse discharge disposition, 1.03 (0.71-1.51); for neurological complications, 1.00 (0.63-1.59); for transfusion, 0.70 (0.41-1.19). Hospital charges were 0.5% lower (range -6 to 5%) in July and August, and LOS was 3% shorter (range -8 to 3%). Odds ratios (95% CI) for July or August shunt surgery compared with shunt surgery performed in other months were as follows: for mortality rate, 0.96 (0.58-1.60); for adverse discharge disposition, 0.85 (0.66-1.11); for neurological complications, 1.27 (0.75-2.16); for transfusion, 0.81 (0.48-1.37). Hospital charges were 0.2% higher in July and August (range -3 to 3%), and LOS was 3% shorter (range -5 to 0.5%).

CONCLUSIONS

Although moderate increases in some adverse end points could not be excluded, there was no evidence that brain tumor or shunt surgery performed in pediatric patients at US teaching hospitals during July and August is associated with more frequent adverse patient outcome or inefficient care than similar surgery performed during other months.

Complications of endovascular treatment of cerebral aneurysms

BACKGROUND

The International Subarachnoid Aneurysm Trial has indicated that endovascular management of acutely ruptured aneurysms may be superior to surgery. Clearly poor results ensue from both forms of treatment, and some of these are because of technical complications (not just poor patient status). This observational study was performed to determine the complications associated with the endovascular treatment of ruptured and unruptured cerebral aneurysms.

METHODS

Prospective data were gathered on 118 patients undergoing 126 endovascular treatment sessions for 126 nontraumatic cerebral aneurysms (30% unruptured) over a 3-year period. The average age was 51 years (range, 12-85 years). Females comprised 75% of the population treated.

RESULTS

Good outcomes were achieved with 71% of the procedures (59% for subarachnoid hemorrhage [SAH]; 97% for unruptured). No bleeding or rebleeding occurred from treated aneurysms. Vessel or aneurysm perforation occurred in 11 cases and led to adverse outcome in 3 (3%). Thromboembolic complications were felt to cause cerebral infarction in 8 cases (6%). The risk of vessel/aneurysm rupture or thromboembolic stroke was greater in patients with SAH. Eight attempts to coil (6%) were initially unsuccessful. Two of these were later successfully coiled and others had surgery. None of the failed attempts led to clinical deterioration. Balloon-assisted coiling (BAC) was not associated with an increased complication rate.

CONCLUSIONS

Vessel perforation and thromboembolic stroke are significant risks of endovascular treatment, especially after SAH. In our hands, however, BAC does not add to this risk.

Safety of intracranial aneurysm surgery performed in a postgraduate training program: implications for training

OBJECT

Patient care and educational experience have long formed a dichotomy in modem surgical training. In neurosurgery, achieving a delicate balance between these two factors has been challenged by recent trends in the field including increased subspecialization, emerging technologies, and decreased resident work hours. In this study the authors evaluated the experience profiles of neurosurgical trainees at a large Canadian academic center and the safety of their practice on patient care.

METHODS

Two hundred ninety-three patients who underwent surgery for intracranial aneurysm clipping between 1993 and 1996 were selected. Prospective data were available in 167 cases, allowing the operating surgeon to be identified. Postoperative data and follow-up data were gathered retrospectively to measure patient outcomes. In 167 cases, a total of 183 aneurysms were clipped, the majority (91%) by neurosurgical trainees. Trainees performed dissections on aneurysms that were predominantly small (< 1.5 cm in diameter; 77% of patients) and ruptured (64% of patients). Overall mortality rates for the patients treated by the trainee group were 4% (two of 52 patients) and 9% (nine of 100 patients) for unruptured and ruptured aneurysm cases, respectively. Patient outcomes were comparable to those reported in historical data. Staff members appeared to be primary surgeons in a select subset of cases.

CONCLUSIONS

Neurosurgical trainees at this institution are exposed to a broad spectrum of intracranial aneurysms, although some case selection does occur. With careful supervision, intracranial aneurysm surgery can be safely delegated to trainees without compromising patient outcomes. Current trends in practice patterns in neurosurgery mandate ongoing monitoring of residents' operative experience while ensuring continued excellence in patient care.

Analysis of intraoperative rupture in the surgical treatment of 1694 saccular aneurysms

OBJECTIVE

Intraoperative rupture (IOR) of an aneurysm is a known risk in the surgical management of intracranial aneurysms. The purpose of this study was to determine the incidence of IOR in a modern surgical series and to assess which factors bear upon it.

METHODS

This study retrospectively examined 1269 patients with saccular aneurysms treated surgically between 1986 and 1998. Three vascular neurosurgeons performed 1435 operations on 1694 aneurysms. Multiple factors, including the magnitude and time of occurrence of IOR, aneurysm location, subarachnoid hemorrhage, timing of surgery, and use of temporary occlusion, were analyzed.

RESULTS

There were 113 instances of IOR (7.9% per surgery; 6.7% per aneurysm; 8.9% per patient). If the 59 "minor leaks" are excluded (as in previously published reports), the incidence becomes 3.8% per surgery, 3.2% per aneurysm, and 4.3% per patient. Posteroinferior cerebellar artery and anterior and posterior communicating artery aneurysms were more liable to rupture intraoperatively. The IOR rate was greater in ruptured than unruptured aneurysms (10.7 versus 1.2%, P < 0.0001). There was a lower rate of IOR in operations using temporary arterial occlusion (3.1 versus 8.6%, P < 0.0001). The occurrence of IOR for early surgery was not significantly higher than for surgery performed more than 3 days after subarachnoid hemorrhage (11.1 versus 10.0%, P = 0.6234).

CONCLUSION

The rate of significant IOR can be kept low. Aneurysm location, subarachnoid hemorrhage, and temporary arterial occlusion seem to be important factors affecting the incidence of IOR.

Early surgery-related complications after aneurysm clip placement: an analysis of causes and patient outcomes

Object. Most reports of series on ruptured intracranial aneurysms contain information on select intraoperative complications. An understanding of all surgical complications, however, may guide us toward improved surgical procedures and enrich discussions concerning alternative management strategies, such as endovascular treatment, which are not exempt from complications and aneurysm recurrence.

Methods. The study consists of a retrospective review of the charts, images, and notes from follow-up visits of 143 consecutive patients with subarachnoid hemorrhage (SAH) who were surgically treated during a 3-year period by one neurosurgeon. A surgical complication was determined based on findings of a clinical and/or radiological study in the absence of confounding factors such as the initial SAH ictus, vasospasm, hydrocephalus, and septic status. Functional outcome was assessed between 2 and 3 months post-SAH by using the Glasgow Outcome Scale (GOS). A procedure-related surgical complication was diagnosed in 29 (20.3%) of 143 patients studied. A brain tissue injury, including cerebral edema and hemorrhagic contusions, was diagnosed in 6.3% of patients, an unpredicted residual aneurysm neck in 5.3% of patients, and a cranial nerve deficit in 2.8% of patients. Functional outcome was good in 22 (75.9%) of the 29 patients with surgical complications. Death due to a surgical complication occurred in one (0.7%) of 143 patients.

Conclusions. Surgical complications are more prevalent than previously thought. They may have been overlooked previously because of the high percentage of good functional outcomes and low mortality rates in this group. The identification of surgical complications may encourage the search for solutions to improve surgical treatment of aneurysmal SAH.

In-hospital Mortality and Morbidity after Surgical Treatment of Unruptured Intracranial Aneurysms in the United States, 1996–2000: The Effect of Hospital and Surgeon Volume

OBJECTIVE

We sought to determine the risk of adverse outcome after contemporary surgical treatment of patients with unruptured intracranial aneurysms in the United States. Patient, surgeon, and hospital characteristics were tested as potential outcome predictors, with particular attention to the surgeon's and hospital's volume of care.

METHODS

We performed a retrospective cohort study with the Nationwide Inpatient Sample, 1996 to 2000. Multivariate logistic and ordinal regression analyses were performed with endpoints of mortality, discharge other than to home, length of stay, and total hospital charges.

RESULTS

We identified 3498 patients who were treated at 463 hospitals, and we identified 585 surgeons in the database. Of all patients, 2.1% died, 3.3% were discharged to skilled-nursing facilities, and 12.8% were discharged to other facilities. The analysis adjusted for age, sex, race, primary payer, four variables measuring acuity of treatment and medical comorbidity, and five variables indicating symptoms and signs. The statistics for median annual number of unruptured aneurysms treated were eight per hospital and three per surgeon. High-volume hospitals had fewer adverse outcomes than hospitals that handled comparatively fewer unruptured aneurysms: discharge other than to home occurred after 15.6% of operations at high-volume hospitals (20 or more cases/yr) compared with 23.8% at low-volume hospitals (fewer than 4 cases/yr) (P = 0.002). High surgeon volume had a similar effect (15.3 versus 20.6%, P = 0.004). Mortality was lower at high-volume hospitals (1.6 versus 2.2%) than at hospitals that handled comparatively fewer unruptured aneurysms, but not significantly so. Patients treated by high-volume surgeons had fewer postoperative neurological complications (P = 0.04). Length of stay was not related to hospital volume. Charges were slightly higher at high-volume hospitals, partly because arteriography was performed more frequently than at hospitals that handled comparatively fewer unruptured aneurysms.

CONCLUSION

For patients with unruptured aneurysms who were treated in the United States between 1996 and 2000, surgery performed at high-volume institutions or by high-volume surgeons was associated with significantly lower morbidity and modestly lower mortality.

[Relation between activity volume and surgeon's results: myth or reality?]

The relationship between volume and surgical outcome seems logical, but needs to be demonstrated in the real world. A qualitative systematic review has been conducted to verify this hypothesis. Five systematic reviews and hundred original papers have been retrieved and analysed. Most of the studies were retrospective and used administrative data instead of medical charts. Moreover few studies involved a good case mix adjustment when comparing surgical units or individual surgeons. These methodological flaws do not allow any evidence based conclusions. Even though a positive relationship is suggested for surgical units, the relationship between volume and outcome was however less obvious for an individual surgeon. There is some evidence that the relationship varied greatly according to the specialty or the procedure evaluated. A new approach based on predictive scores comparing expected versus observed outcomes is mandatory and seems to be the best way to assess objectively the relationship between surgical volume and outcomes.