Noojan Kazemi

Epilepsy surgery outcomes in temporal lobe epilepsy with a normal MRI.

Purpose:  To determine the long‐term efficacy of anterior temporal lobectomy for medically refractory temporal lobe epilepsy in patients with nonlesional magnetic resonance imaging (MRI).

Incidence and prevalence of surgery at segments adjacent to a previous posterior lumbar arthrodesis

BACKGROUND CONTEXT Adjacent segment disease (ASD) after lumbar spinal fusion has been an important reason behind the development of nonfusion stabilization technology. However, the incidence, prevalence, and factors contributing to adjacent segment degeneration in the lumbar spine remain unclear. A range of prevalence rates for ASD have been reported in the lumbar spinal literature, but the annual incidence has not been widely studied in this region. Conflicting reports exist regarding risk factors, especially fusion length. PURPOSE To determine the annual incidence and prevalence of further surgery for adjacent segment disease (SxASD) after posterior lumbar arthrodesis and examine possible risk factors. STUDY DESIGN Retrospective cohort study. PATIENT SAMPLE Nine hundred twelve patients who underwent 1,000 consecutive posterior lumbar interbody fusion procedures, with mean follow-up duration of 63 months (range, 5 months-16 years). OUTCOME MEASURES Further surgery for ASD or surgery-free survival. METHODS A postal and telephone survey. Follow-up rate: 91% of patients. The annual incidence and prevalence of ASD requiring further surgery were determined using Kaplan-Meier survivorship analysis. Cox proportional-hazards (Cox) regression was used for multivariate analysis of possible risk factors. Significance was set at p<.05. RESULTS Further surgery for ASD occurred following 130 of 1,000 or 13% of procedures at a mean time of 43 months (range, 2.3-162 months). The mean annual incidence of SxASD over the first 10 years, in all patients, was 2.5% (95% confidence interval [95% CI], 1.9-3.1) with prevalences of 13.6% and 22.2% at 5 and 10 years, respectively. Cox regression modeling found that the number of levels fused (p≤.0003), age of the patient, fusing to L5, and performing an additional laminectomy adjacent to a fusion all independently affect the risk of SxASD. The mean annual incidence figures in the first 10 years after a lumbar fusion were 1.7% (95% CI, 1.3-2.2) after fusion at single levels, 3.6% (2.1-5.2) after two levels, and 5.0% (3.3-6.7) after three and four levels. The 5- and 10-year prevalences were 9% and 16%, 17% and 31%, and 29% and 40% after single-, two-, and three-/four-level fusions, respectively. The risk of SxASD in patients younger than 45 years was one-quarter (95% CI, 10-64) the risk of patients older than 60 years (p=.003). A laminectomy adjacent to a fusion increases the relative risk by 2.4 times (95% CI, 1.1-5.2; p=.03). Stopping a fusion at L5 is associated with a 1.7-fold increased risk (95% CI, 1.2-2.4; p=.007) of SxASD compared with a fusion to S1, for fusions of the same length. CONCLUSION The overall annual incidence and predicted 10-year prevalence of further surgery for ASD after lumbar arthrodesis were 2.5% and 22.2%, respectively. These rates varied widely depending on the identified risk factors. Although young patients who underwent single-level fusions were at low risk, patients who underwent fusion of three or four levels had a threefold increased risk of further surgery, compared with single-level fusions (p<.0001), and a predicted 10-year prevalence of 40%.

Restarting Anticoagulation Therapy After Warfarin-Associated Intracerebral Hemorrhage

BACKGROUND Reinitiating warfarin sodium therapy in a patient with a recent warfarin-related intracerebral hemorrhage (WAICH) is a difficult clinical decision. Therefore, it is important to assess the outcome of resumption or discontinuation of warfarin therapy after WAICH. OBJECTIVE To compare patients who survived an episode of WAICH and restarted warfarin therapy with a group of WAICH patients who did not resume warfarin therapy. Design, Setting, and Patients We conducted a follow-up study from November 1, 2001, through December 31, 2005, in a cohort from a single center. Long-term outcome was assessed at last clinical follow-up or via questionnaire. MAIN OUTCOME MEASURES Recurrent WAICH and thromboembolic events. RESULTS Fifty-two patients were discharged from the hospital after a diagnosis of WAICH. Four patients were lost to follow-up. Mean follow-up among all patients was 43 (range, 1-108) months. Of the 23 patients who restarted warfarin therapy, 1 had a recurrent nontraumatic WAICH, 2 had traumatic intracerebral hemorrhages, and 2 had major extracranial hemorrhages. Of the 25 patients who did not restart warfarin therapy, 3 had a thromboembolic stroke, 1 had a pulmonary embolus, and 1 had a distal arterial embolus. CONCLUSIONS Restarting warfarin therapy in patients with a recent WAICH is associated with a low risk of recurrence, but patients are subjected to known, substantial risks of warfarin use. Withholding warfarin therapy is associated with a risk of thromboembolization.

Ictal SPECT statistical parametric mapping in temporal lobe epilepsy surgery.

Objective: Although subtraction ictal SPECT coregistered to MRI (SISCOM) is clinically useful in epilepsy surgery evaluation, it does not determine whether the ictal–interictal subtraction difference is statistically different from the expected random variation between 2 SPECT studies. We developed a statistical parametric mapping and MRI voxel-based method of analyzing ictal–interictal SPECT difference data (statistical ictal SPECT coregistered to MRI [STATISCOM]) and compared it with SISCOM. Methods: Two serial SPECT studies were performed in 11 healthy volunteers without epilepsy (control subjects) to measure random variation between serial studies from individuals. STATISCOM and SISCOM images from 87 consecutive patients who had ictal SPECT studies and subsequent temporal lobectomy were assessed by reviewers blinded to clinical data and outcome. Results: Interobserver agreement between blinded reviewers was higher for STATISCOM images than for SISCOM images (κ = 0.81 vs κ = 0.36). STATISCOM identified a hyperperfusion focus in 84% of patients, SISCOM in 66% (p < 0.05). STATISCOM correctly localized the temporal lobe epilepsy (TLE) subtypes (mesial vs lateral neocortical) in 68% of patients compared with 24% by SISCOM (p = 0.02); subgroup analysis of patients without lesions (as determined by MRI) showed superiority of STATISCOM (80% vs 47%; p = 0.04). Moreover, the probability of seizure-free outcome was higher when STATISCOM correctly localized the TLE subtype than when it was indeterminate (81% vs 53%; p = 0.03). Conclusion: Statistical ictal SPECT coregistered to MRI (STATISCOM) was superior to subtraction ictal SPECT coregistered to MRI for seizure localization before temporal lobe epilepsy (TLE) surgery. STATISCOM localization to the correct TLE subtype was prognostically important for postsurgical seizure freedom.

Resection of Frontal Encephalomalacias for Intractable Epilepsy: Outcome and Prognostic Factors

Summary: Purpose: Because focal encephalomalacia is an important cause of medically intractable partial epilepsy and few studies have evaluated the efficacy and the safety of resecting focal encephalomalacias to improve seizure control, we studied a cohort of 17 consecutive patients who underwent resection of encephalomalacias in the frontal lobes as a treatment of their intractable epilepsy.

Preoperative Predictors of Spinal Infection within the National Surgical Quality Inpatient Database.

BACKGROUND Surgical-site infections (SSIs) are a major cause of morbidity and mortality, increasing the length and cost of hospitalization. In patients undergoing spine surgery, there are limited large-scale data on patient-specific risk factors for SSIs. METHODS The American College of Surgeons National Surgical Quality Improvement Program database was reviewed for all spinal operations between 2006 and 2012. The rates of 30-day SSIs were calculated, and univariate analysis of selected preoperative risk factors was performed. Multivariate analysis was then used to identify independent predictors of SSIs. RESULTS A total of 1110 of the 60,179 patients (1.84%) had a postoperative wound infection. There were 527 (0.87%) deep and 590 (0.98%) superficial infections. Patients with infections had greater rates of sepsis, longer lengths of stay, and more return visits to the operating room. Independent predictors of infection were female sex, inpatient status, insulin-dependent diabetes, preoperative steroid use greater than 10 days, hematocrit less than 35, body mass index greater than 30, wound class, American Society of Anesthesiologists class, and operative duration. CONCLUSIONS Analysis of a large national patient database revealed many independent risk factors for SSIs after spinal surgery. Some of these risk factors can be modified preoperatively to reduce the risk of postoperative infection.

Statistical Parametric Mapping Demonstrates Asymmetric Uptake with Tc-99m ECD and Tc-99m HMPAO SPECT in Normal Brain

Tc-99m ethyl cysteinate diethylester (ECD) and Tc-99m hexamethyl propylene amine oxime (HMPAO) are commonly used for single-photon emission computed tomography (SPECT) studies of a variety of neurologic disorders. Although these tracers have been very helpful in diagnosing and guiding treatment of neurologic disease, data describing the distribution and laterality of these tracers in normal resting brain are limited. Advances in quantitative functional imaging have demonstrated the value of using resting studies from control populations as a baseline to account for physiologic fluctuations in cerebral perfusion. Here, we report results from 30 resting Tc-99m ECD SPECT scans and 14 resting Tc-99m HMPAO scans of normal volunteers with no history of neurologic disease. Scans were analyzed with regions of interest and with statistical parametric mapping, with comparisons performed laterally (left vs. right), as well as for age, gender, and handedness. The results show regions of significant asymmetry in the normal controls affecting widespread areas in the cerebral hemispheres, but most marked in superior parietotemporal region and frontal lobes. The results have important implications for the use of normal control SPECT images in the evaluation of patients with neurologic disease.

The future of spine surgery: New horizons in the treatment of spinal disorders.

Background and Methods: As with any evolving surgical discipline, it is difficult to predict the future of the practice and science of spine surgery. In the last decade, there have been dramatic developments in both the techniques as well as the tools employed in the delivery of better outcomes to patients undergoing such surgery. In this article, we explore four specific areas in spine surgery: namely the role of minimally invasive spine surgery; motion preservation; robotic-aided surgery and neuro-navigation; and the use of biological substances to reduce the number of traditional and revision spine surgeries. Results: Minimally invasive spine surgery has flourished in the last decade with an increasing amount of surgeries being performed for a wide variety of degenerative, traumatic, and neoplastic processes. Particular progress in the development of a direct lateral approach as well as improvement of tubular retractors has been achieved. Improvements in motion preservation techniques have led to a significant number of patients achieving arthroplasty where fusion was the only option previously. Important caveats to the indications for arthroplasty are discussed. Both robotics and neuro-navigation have become further refined as tools to assist in spine surgery and have been demonstrated to increase accuracy in spinal instrumentation placement. There has much debate and refinement in the use of biologically active agents to aid and augment function in spine surgery. Biological agents targeted to the intervertebral disc space could increase function and halt degeneration in this anatomical region. Conclusions: Great improvements have been achieved in developing better techniques and tools in spine surgery. It is envisaged that progress in the four focus areas discussed will lead to better outcomes and reduced burdens on the future of both our patients and the health care system.

Multidisciplinary surgical treatment of presacral meningocele and teratoma in an adult with Currarino triad

Background: Currarino syndrome (CS) is a rare genetic condition that presents with the defining triad of anorectal malformations, sacral bone deformations, and presacral masses, which may include teratoma. Neurosurgeons are involved in the surgical treatment of anterior meningoceles, which are often associated with this condition. The accepted surgical treatment is a staged anterior-posterior resection of the presacral mass and obliteration of the anterior meningocele. Case Description: This case involved a 36-year-old female who presented with late onset of symptoms attributed to CS (e.g., presacral mass, anterior sacral meningocele, and sacral agenesis). She successfully underwent multidisciplinary single-stage approach for treatment of the anterior sacral meningocele and resection of the presacral mass. This required obliteration of the meningocele and closure of the dural defect. One year later, her meningocele had fully resolved. Conclusion: While late presentations with CS are rare, early detection and multidisciplinary treatment including single-state anterior may be successful for managing these patients.

Utility of positron emission tomography in schwannomatosis

Schwannomatosis is characterized by multiple non-intradermal schwannomas with patients often presenting with a painful mass in their extremities. In this syndrome malignant transformation of schwannomas is rare in spite of their large size at presentation. Non-invasive measures of assessing the biological behavior of plexiform neurofibromas in neurofibromatosis type 1 such as positron emission tomography (PET), CT scanning and MRI are well characterized but little information has been published on the use of PET imaging in schwannomatosis. We report a unique clinical presentation portraying the use of PET imaging in schwannomatosis. A 27-year-old woman presented with multiple, rapidly growing, large and painful schwannomas confirmed to be related to a constitutional mutation in the SMARCB1 complex. Whole body PET/MRI revealed numerous PET-avid tumors suggestive of malignant peripheral nerve sheath tumors. Surgery was performed on multiple tumors and none of them had histologic evidence of malignant transformation. Overall, PET imaging may not be a reliable predictor of malignant transformation in schwannomatosis, tempering enthusiasm for surgical interventions for tumors not producing significant clinical signs or symptoms.