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Walter A. Hall, Edward Rustamzadeh, and Anthony L. Asher

The poor prognosis associated with the current management of malignant gliomas has led investigators to develop alternative treatments such as targeted toxin therapy. The optimal method for administering these agents is under development but appears to be convection-enhanced delivery (CED).

The direct intratumoral infusion of targeted toxins was first performed in nude mouse flank tumor models of human malignant glioma. After the demonstration of in vivo efficacy, these potent cytotoxic compounds were tested in Phase I and Phase II clinical trials.

Using a high-flow microinfusion technique, volumes of up to 180 ml were infused by CED through catheters placed directly into brain tumors. Minor systemic toxicity was seen in the form of hepatic enzyme elevation. Neural toxicity manifested as seizure activity and hemiparesis resulted from peritumoral edema that followed the completion of the infusion. Peritumoral toxicity was believed to be more related to the concentration of the infused immunotoxin than to the infusion volume. In approximately half of patients treated with CED a stable disease course, a partial response, or a complete response was demonstrated in some clinical trials.

Targeted toxin therapy has clinical efficacy in patients with malignant gliomas. Convection-enhanced delivery appears to represent an effective method for administering these agents in patients with malignant brain tumors.

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Anthony L. Asher, Matthew J. McGirt, and Zoher Ghogawala

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Matthew J. McGirt, Ahilan Sivaganesan, Anthony L. Asher, and Clinton J. Devin

OBJECT

Lumbar spine surgery has been demonstrated to be efficacious for many degenerative spine conditions. However, there is wide variability in outcome after spine surgery at the individual patient level. All stakeholders in spine care will benefit from identification of the unique patient or disease subgroups that are least likely to benefit from surgery, are prone to costly complications, and have increased health care utilization. There remains a large demand for individual patient-level predictive analytics to guide decision support to optimize outcomes at the patient and population levels.

METHODS

One thousand eight hundred three consecutive patients undergoing spine surgery for various degenerative lumbar diagnoses were prospectively enrolled and followed for 1 year. A comprehensive patient interview and health assessment was performed at baseline and at 3 and 12 months after surgery. All predictive covariates were selected a priori. Eighty percent of the sample was randomly selected for model development, and 20% for model validation. Linear regression was performed with Bayesian model averaging to model 12-month ODI (Oswestry Disability Index). Logistic regression with Bayesian model averaging was used to model likelihood of complications, 30-day readmission, need for inpatient rehabilitation, and return to work. Goodness-of-fit was assessed via R2 for 12-month ODI and via the c-statistic, area under the receiver operating characteristic curve (AUC), for the categorical endpoints. Discrimination (predictive performance) was assessed, using R2 for the ODI model and the c-statistic for the categorical endpoint models. Calibration was assessed using a plot of predicted versus observed values for the ODI model and the Hosmer-Lemeshow test for the categorical endpoint models.

RESULTS

On average, all patient-reported outcomes (PROs) were improved after surgery (ODI baseline vs 12 month: 50.4 vs 29.5%, p < 0.001). Complications occurred in 121 patients (6.6%), 108 (5.9%) were readmitted within 30 days of surgery, 188 (10.3%) required discharge to inpatient rehabilitation, 1630 (88.9%) returned to work, and 449 (24.5%) experienced an unplanned outcome (no improvement in ODI, a complication, or readmission). There were 45 unique baseline variable inputs, derived from 39 clinical variables and 38 questionnaire items (ODI, SF-12, MSPQ, VAS-BP, VAS-LP, VAS-NP), included in each model. For prediction of 12-month ODI, R2 was 0.51 for development and 0.47 for the validation study. For prediction of a complication, readmission, inpatient rehabilitation, and return to work, AUC values ranged 0.72-0.84 for development and 0.79-0.84 for validation study.

CONCLUSIONS

A novel prediction model utilizing both clinical data and patient interview inputs explained the majority of variation in outcome observed after lumbar spine surgery and reliably predicted 12-month improvement in physical disability, return to work, major complications, readmission, and need for inpatient rehabilitation for individual patients. Application of these models may allow clinicians to offer spine surgery specifically to those who are most likely to benefit and least likely to incur complications and excess costs.

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Anthony L. Asher, Clinton J. Devin, Robert E. Harbaugh, and Mohamad Bydon

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Anthony L. Asher, Paul C. McCormick, and Douglas Kondziolka

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Charles H. Crawford III, Leah Y. Carreon, Mohamad Bydon, Anthony L. Asher, and Steven D. Glassman

OBJECTIVE

Patient satisfaction is a commonly used metric in the current health care environment. While factors that affect patient satisfaction following spine surgery are complex, the authors of this study hypothesized that specific diagnostic groups of patients are more likely to be satisfied after spine surgery and that this is reflected in patient-reported outcome measures. The purpose of this study was to determine if the preoperative diagnosis—disc herniation, stenosis, spondylolisthesis, adjacent segment degeneration, or mechanical disc collapse—would impact patient satisfaction following surgery.

METHODS

Patients enrolled in the Quality Outcomes Database, formerly known as the National Neurosurgery Quality and Outcomes Database (N2QOD), completed patient-reported outcome measures, including the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) for back pain (NRS-BP) and leg pain (NRS-LP) preoperatively and 1-year postoperatively. Patients were stratified by diagnosis and by their response to the satisfaction question: 1) surgery met my expectations; 2) I did not improve as much as I hoped, but I would undergo the same operation for the same results; 3) surgery helped, but I would not undergo the same operation for the same results; or 4) I am the same or worse as compared with before surgery.

RESULTS

A greater proportion of patients with primary disc herniation or spondylolisthesis reported that surgery met expectations (66% and 67%, respectively), followed by recurrent disc herniation and stenosis (59% and 60%, respectively). A smaller proportion of patients who underwent surgery for adjacent segment degeneration or mechanical disc collapse had their expectations met (48% and 41%, respectively). The percentage of patients that would undergo the same surgery again, by diagnostic group, was as follows: disc herniation 88%, recurrent disc herniation 79%, spondylolisthesis 86%, stenosis 82%, adjacent segment disease 75%, and mechanical collapse 73%. Regardless of diagnosis, mean improvement and ultimate 1-year postoperative ODI, NRS-BP, and NRS-LP reflected patient satisfaction.

CONCLUSIONS

Preoperative diagnosis was predictive of patient satisfaction following spine surgery. The mean change in and 1-year ODI, NRS-BP, and NRS-LP reflected patient satisfaction regardless of preoperative diagnosis.

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Robert E. Harbaugh, Anthony L. Asher, Kevin M. Cockroft, John Knightly, and Ganesalingam Narenthiran