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

Influence of trends in hospital volume over time on patient outcomes for high-risk surgery

BACKGROUND

The "practice makes perfect" concept considers the more frequent a hospital performs a procedure, the better the outcome of the procedure. We aimed to study this concept by investigating whether patient outcomes improve in hospitals with a significantly increased volume of high-risk surgery over time and whether a learning effect existed at the individual hospital level.

METHODS

We included all patients who underwent one of 10 digestive, cardiovascular and orthopaedic procedures between 2010 and 2014 from the French nationwide hospitals database. For each procedure, we identified three groups of hospitals according to volume trend (increased, decreased, or no change). In-hospital mortality, reoperation, and unplanned hospital readmission within 30 days were compared between groups using Cox regressions, taking into account clustering of patients within hospitals and potential confounders. Individual hospital learning effect was investigated by considering the interaction between hospital groups and procedure year.

RESULTS

Over 5 years, 759,928 patients from 694 hospitals were analysed. Patients' mortality in hospitals with procedure volume increase or decrease over time did not clearly differ from those in hospitals with unchanged volume across the studied procedures (e.g., Hazard Ratios [95%] of 1.04 [0.93-1.17] and 1.08 [0.97-1.21] respectively for colectomy). Furthermore, patient outcomes did not improve or deteriorate in hospitals with increased or decreased volume of procedures over time (e.g., 1.01 [0.95-1.08] and 0.99 [0.92-1.05] respectively for colectomy).

CONCLUSIONS

Trend in hospital volume over time did not appear to influence patient outcomes based on real-world data.

TRIAL REGISTRATION

NCT02788331, June 2, 2016.

Operative volume and outcomes of cerebrovascular neurosurgery in children

OBJECTIVE The impact of procedural volume on the outcomes of cerebrovascular surgery in children has not been determined. In this study, the authors investigated the association of operative volume on the outcomes of cerebrovascular neurosurgery in pediatric patients. METHODS The authors performed a cohort study of all pediatric patients who underwent a cerebrovascular procedure between 2003 and 2012 and were registered in the Kids' Inpatient Database (KID). To control for confounding, the authors used multivariable regression models, propensity-score conditioning, and mixed-effects analysis to account for clustering at the hospital level. RESULTS During the study period, 1875 pediatric patients in the KID underwent cerebrovascular neurosurgery and met the inclusion criteria for the study; 204 patients (10.9%) underwent aneurysm clipping, 446 (23.8%) underwent coil insertion for an aneurysm, 827 (44.1%) underwent craniotomy for arteriovenous malformation resection, and 398 (21.2%) underwent bypass surgery for moyamoya disease. Mixed-effects multivariable regression analysis revealed that higher procedural volume was associated with fewer inpatient deaths (OR 0.58; 95% CI 0.40-0.85), a lower rate of discharges to a facility (OR 0.87; 95% CI 0.82-0.92), and shorter length of stay (adjusted difference -0.22; 95% CI -0.32 to -0.12). The results in propensity-adjusted multivariable models were robust. CONCLUSIONS In a national all-payer cohort of pediatric patients who underwent a cerebrovascular procedure, the authors found that higher procedural volume was associated with fewer deaths, a lower rate of discharges to a facility, and decreased lengths of stay. Regionalization initiatives should include directing children with such rare pathologies to a center of excellence.

The impact of hybrid neurosurgeons on the outcomes of endovascular coiling for unruptured cerebral aneurysms

OBJECTIVE The impact of combined practices on the outcomes of unruptured cerebral aneurysm coiling remains an issue of debate. The authors investigated the association of combined open and endovascular expertise with the outcomes of unruptured cerebral aneurysm coiling. METHODS The authors performed a cohort study of 100% of Medicare fee-for-service claims data for elderly patients who underwent endovascular coiling for unruptured cerebral aneurysms between 2007 and 2012. To control for confounding, the authors used propensity score conditioning, with mixed effects to account for clustering at the hospital referral region level. RESULTS During the study period, there were 11,716 patients who underwent endovascular coiling for unruptured cerebral aneurysms and met the inclusion criteria. Of these, 1186 (10.1%) underwent treatment performed by hybrid neurosurgeons, and 10,530 (89.9%) by proceduralists who performed only endovascular coiling. Multivariable regression analysis with propensity score adjustment demonstrated a lack of association of combined practice with 1-year postoperative mortality (OR 0.84; 95% CI 0.58-1.23), discharge to rehabilitation (OR 1.0; 95% CI 0.66-1.51), 30-day readmission rate (OR 1.07; 95% CI 0.83-1.38), and length of stay (adjusted difference, 0.41; 95% CI -0.26 to 1.09). Higher procedural volume was independently associated with improved outcomes. CONCLUSIONS In a cohort of Medicare patients, the authors did not demonstrate a difference in mortality, discharge to rehabilitation, readmission rate, and LOS between hybrid neurosurgeons and proceduralists performing only endovascular coiling.

Unruptured cerebral aneurysm clipping: association of combined open and endovascular expertise with outcomes

BACKGROUND

It is often questioned if one physician can conduct both open and endovascular techniques successfully and safely.

OBJECTIVE

To investigate the association of combined open and endovascular expertise with the outcomes of unruptured cerebral aneurysm clipping.

METHODS

We performed a cohort study of 100% of Medicare fee-for-service claims data for elderly patients who underwent surgical clipping for unruptured cerebral aneurysms between 2007 and 2012. To control for confounding we used propensity score conditioning, and controlled for clustering at the physician level.

RESULTS

During the study, 3247 patients underwent clipping for unruptured cerebral aneurysms, and met the inclusion criteria. Of these, 766 (23.6%) underwent treatment by hybrid neurosurgeons, and 2481 (76.4%) by proceduralists, who performed only clipping. Multivariable regression analysis with propensity score adjustment demonstrated a lack of association of combined practice with 1-year postoperative mortality (OR=0.81; 95% CI 0.51 to 1.28), discharge to rehabilitation (OR=0.95; 95% CI 0.72 to 1.25), length of stay (adjusted difference 0.85 days; 95% CI -0.31 to 2.00), or 30-day readmission rate (OR=1.05; 95% CI 0.80 to 1.39). Higher procedural volume was independently associated with improved outcomes.

CONCLUSIONS

In a cohort of Medicare patients with unruptured aneurysms, we did not demonstrate a difference in mortality, discharge to rehabilitation, or readmission rate between hybrid neurosurgeons and surgeons performing only clipping.

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.

Surgical treatment of unruptured intracranial aneurysms in a low-volume hospital--outcome and review of literature

BACKGROUND

The aim of this study was to evaluate surgical outcome of unruptured intracranial aneurysms (UIAs) in a low-volume hospital and compare the results with the recent literature.

METHODS

A retrospective review of all consecutive craniotomies for UIA from July 1999 through June 2009 was performed. Morbidity was defined as modified Rankin Scale (mRS) ≥ 3 and evaluated six weeks after surgery. Cognitive function was evaluated at rehabilitation-to-home discharge. A PubMed database search (2001-2011) seeking retrospective, single-center studies reporting on surgical outcome of UIAs was performed.

RESULTS

There were 47 procedures performed in 42 patients to treat 50 UIAs (mean of 5 annual craniotomies). The mean age was 54.7 ± 12.1 years and mean aneurysm size was 7.6 ± 4.0mm. Favorable outcome (mRS 0-2) at six weeks after surgery was achieved in 45 of 47 procedures (95.7%). Aneurysm size ≥ 12 mm was statistically significant related to adverse outcome defined as mRS change ≥ 1 (71% vs. 29%; p = 0.018). Five patients (10.6%) with favorable neurological outcome (mRS 2) presented with cognitive impairment at rehabilitation-to-home discharge. There was no significant difference in overall morbidity and mortality comparing low- and high-volume hospitals (4.0% vs. 4.8%; p = 0.85).

CONCLUSIONS

Low-volume hospitals may achieve good results for surgical treatment of UIAs. The results indicate that defining numeric operative volume thresholds is not feasible to guide centralization of aneurysm treatment.