✓ The authors report on the technique and results of stereotactic biopsy for intrinsic lateral pontine and medial cerebellar lesions via a contralateral, transfrontal, extraventricular approach. Multiplanar stereotactic magnetic resonance imaging was used to plan an intraparenchymal approach, thus limiting the number of crossed pial surfaces to one and eliminating the need to cross ependymal surfaces. After the administration of a local anesthetic agent with light intravenous sedation, six patients harboring intrinsic lateral pontine lesions underwent biopsies via this intraparenchymal approach with 100% diagnostic yield and no operative morbidity. In comparison to the ipsilateral transfrontal approach, the contralateral approach laterally expands the infratentorial area accessible during biopsy to include the lateral pons and middle cerebellar peduncle. The contralateral, transfrontal, extraventricular approach is a useful, straight-forward and safe alternative to the suboccipital transcerebellar and ipsilateral, transfrontal, transtentorial routes for reaching lesions of the lateral pons and middle cerebellar peduncle.
Eric W. Amundson, Matthew J. McGirt, and Alessandro Olivi
Anthony L. Asher, Matthew J. McGirt, and Zoher Ghogawala
Matthew J. McGirt, Shlomi Constantini, and George I. Jallo
Postoperative progressive spinal deformity often complicates functional outcome after resection of pediatric intramedullary spinal cord tumors (IMSCTs). The authors propose a preoperative grading scale that correlates with the postoperative development of progressive spinal deformity requiring subsequent fusion.
The data obtained in 164 patients who underwent resection of an IMSCT at a single institution were retrospectively collected and analyzed to determine the development of progressive spinal deformity requiring fusion. A grading scale (range of scores I–V) was created based on the presence or absence of 4 preoperative variables: preoperative scoliosis, involvement of the thorocolumbar junction, age < 13 years, and number of surgeries for an IMSCT. The grading scale was then retrospectively applied to this series of 164 children to assess the correlation of variables with subsequent spinal deformity.
Nine patients presented with Grade I status, 41 patients with Grade II, 58 patients with Grade III, 44 patients with Grade IV, and 12 patients with Grade V. Overall, 44 patients (27%) developed progressive spinal deformity requiring fusion at a mean follow-up of 5 years after surgery. A higher preoperative grade was associated with an increasing need for subsequent fusion for progressive spinal deformity (Grade I [0%], Grade II [5%], Grade III [26%], Grade IV [40%], and Grade V status [75%]).
Application of this grading scheme to a series of resected pediatric IMSCTs has demonstrated its correlation with the incidence of postoperative progressive spinal deformity requiring fusion. The application of a standardized grading scheme will assist in the process of surgical decision making and postoperative evaluation.
John R. W. Kestle
Joseph H. Piatt Jr.
Matthew J. McGirt, Ahilan Sivaganesan, Anthony L. Asher, and Clinton J. Devin
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.
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.
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.
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.
Matthew J. McGirt, Giannina L. Garces Ambrossi, Judy Huang, and Rafael J. Tamargo
Vasospasm is the major cause of disability and death after aneurysmal subarachnoid hemorrhage (aSAH). Although the results of 2 randomized clinical trials demonstrated that statin decreases the incidence of symptomatic cerebral vasospasm after aSAH, retrospective studies have failed to confirm this. The authors conducted a prospective observational study to determine whether a standardized regimen of simvastatin would reduce the incidence of cerebral vasospasm and improve neurological outcomes in patients with aSAH.
Since 1991, all patients with aSAH admitted to the authors' institution have been prospectively followed up with standardized outcomes recording. Starting in September 2005, all patients admitted with aSAH were given enteral simvastatin (80 mg/day for 14 days) in addition to the standard care. The incidence of symptomatic cerebral vasospasm, length of hospitalization, in-hospital mortality rate, and discharge Glasgow Outcome Scale scores in these 170 patients were compared to data obtained in 170 consecutive patients who underwent treatment in our unit prior to the introduction of statin therapy.
The 5-year study period included 340 consecutively treated patients (170 who received statins and 170 who did not). Patients who received simvastatin therapy were more frequently male (29 vs 20%) and had a smaller median aneurysm diameter (6 vs 7 mm). Baseline characteristics were otherwise similar between the cohorts. There were no differences in the incidence of symptomatic vasospasm (25.3 vs 30.5%; p = 0.277), in-hospital mortality rate (18 vs 15%; p = 0.468), length of hospitalization (21 ± 15 vs 19 ± 12 days; p = 0.281), or poor outcome at discharge (Glasgow Outcome Scale Scores 1–2: 21.7 vs 18.2%; p = 0.416) between the simvastatin and nonstatin cohorts. There were no statin-related complications.
The uniform introduction of simvastatin did not reduce the incidence of symptomatic cerebral vasospasm, death, or poor outcome in patients with aSAH. Simvastatin was well tolerated, but its benefit may be less than has been previously reported.
R. Shane Tubbs, Matthew J. McGirt, and W. Jerry Oakes
Object. The aim of this study was to present the long-term findings of a surgical series of pediatric patients with Chiari I malformations.
Methods. One hundred thirty symptomatic pediatric patients with Chiari I malformations underwent posterior fossa decompression. The age in this group of patients ranged from 2 months to 20 years (mean 11 years). The length of the hospital stay extended from 2 to 7 days (mean 2.7 days), and follow up was from 3 months to 15 years (mean 4.2 years). Patients most often presented with headache/neck pain (38%) and scoliosis (18%). Examples of associated diagnoses included neurofibromatosis Type 1 (5.5%), hydrocephalus (11%), idiopathic growth hormone deficiency (5.5%), and Klippel—Feil anomaly (5%). Syringes were present in 58% of patients. Seventeen percent of patients had caudal displacement of the brainstem and fourth ventricle. Postoperative relief of preoperative pathologies was experienced in 83% of patients. Of the most common presenting symptoms—headache/neck pain and scoliosis—12 and 17%, respectively, were not alleviated postoperatively. Complications occurred in 2.3% of this group and included the development of acute hydrocephalus postoperatively and severe life-threatening signs of brainstem compression that necessitated a transoral odontoidectomy. Nine patients have had to undergo repeated operations for continued symptoms or persistent large syringes. During surgery 10 patients (7.7%) were found to have arachnoid veils occluding the fourth ventricular outlet, and nine of these had syringomyelia. In our experience almost all syringes will stabilize or improve with posterior fossa decompression and duraplasty.
Conclusions. The authors believe this to be the largest reported series of pediatric patients who have undergone posterior fossa decompression for Chiari I malformations.