Gautam Nayar

Leptomeningeal disease: current diagnostic and therapeutic strategies

Leptomeningeal disease has become increasingly prevalent as novel therapeutic interventions extend the survival of cancer patients. Although a majority of leptomeningeal spread occurs secondary to breast cancer, lung cancer, and melanoma, a wide variety of malignancies have been reported as primary sources. Symptoms on presentation are equally diverse, often involving a combination of neurological deficits with the possibility of obstructive hydrocephalus. Diagnosis is definitively made via cerebrospinal fluid cytology for malignant cells, but neuro-imaging with high quality T1-weighted magnetic resonance imaging can aid diagnosis and localization. While leptomeningeal disease is still a terminal, late-stage complication, a variety of treatment modalities, such as intrathecal chemotherapeutics and radiation therapy, have improved median survival from 4–6 weeks to 3–6 months. Positive prognosticative factors for survival include younger age, high performance scores, and controlled systemic disease. In looking to the future, diagnostics that improve early detection and chemotherapeutics tailored to the primary malignancy will likely be the most significant advances in improving survival.

Bony Lateral Recess Stenosis and Other Radiographic Predictors of Failed Indirect Decompression via Extreme Lateral Interbody Fusion: Multi-Institutional Analysis of 101 Consecutive Spinal Levels

OBJECTIVE Although extreme lateral interbody fusion (XLIF) largely provides successful indirect decompression, some patients have recurrent same-level pain and functional disability. Identifying risk factors for this failure would facilitate better patient selection and improve outcomes. The aim of this study is to identify preoperative radiographic risk factors for failure of XLIF. METHODS Patients undergoing XLIF were prospectively enrolled by 3 surgeons at 3 separate institutions. Radiographic variables measured included (1) anterior and posterior disc height, (2) foramen height and area, (3) central canal diameter, (4) central canal area, (5) right and left subarticular diameters, (6) facet arthropathy grade, and (7) presence of bony lateral recess stenosis. Patients failed indirect decompression if Oswestry Disability Index (ODI) scores did not improve by 20 points or revision surgery was required within 6 months postoperatively. Univariate and multivariate analyses were performed to identify radiographic predictors of failure of indirect decompression. RESULTS Of the 45 patients (age 65.6 ± 10.5 years; 14 male) involving 101 spinal levels included in this study, 13 (29%) failed indirect decompression. From univariate analysis, these patients had significantly smaller central canal diameter, foraminal height, and disc height (P < 0.05). In multivariate analysis of these parameters and those trending toward significance, bony lateral recess stenosis was the only significant independent predictor for failure of indirect decompression (coefficient, 0.55 [0.24-0.85]; P < 0.001). CONCLUSIONS Bony lateral recess stenosis is an independent predictor for failure to achieve adequate spinal decompression via XLIF and thus may benefit from undergoing direct decompression.

Independent predictors of mortality following spine surgery.

We investigated the effect of preoperative patient demographics and operative factors on mortality in the 30day postoperative period after spine surgery. Postoperative mortality from surgical interventions has significantly decreased with progressive improvement in surgical techniques and patient selection. Well-studied preoperative risk factors include age, obesity, emphysema, clotting disorders, renal failure, and cardiovascular disease. However, the prognostic implications of such risk factors after spine surgery specifically remain unknown. The medical records of all consecutive patients undergoing spine surgery from 2008-2010 at our institution were reviewed. Patient demographics, comorbidities, indication for operation, surgical details, postoperative complications, and mortalities were collected. The association between preoperative demographics or surgical details and postoperative mortality was assessed via logistic regression analysis. All 1344 consecutive patients (1153 elective, 191 emergency) met inclusion criteria for the study; 19 (1.4%) patients died in the 30days following surgery. Multivariable logistic regression found several predictive factors of mortality for all spine surgery patients: operation in the cervical area (odds ratio [OR]: 7.279, 95% confidence interval [CI]: 1.37-42.83, p=0.02), postoperative sepsis (OR: 5.75, 95% CI: 1.16-26.38, p=0.03), operation for neoplastic (OR: 7.68, 95% CI: 1.53-42.71, p=0.01) or traumatic (OR: 13.76, 95% CI: 2.40-88.68, p=0.03) etiology, and age as defined as a continuous variable (OR: 1.05, 95% CI: 1.01-1.10, p=0.03). This study demonstrates predictive factors to help identify and evaluate patients who are at higher risk for mortality from spinal surgery, and potentially devise methods to reduce this risk.

Impact of Affective Disorders on Recovery of Baseline Function in Patients Undergoing Spinal Surgery: A Single Institution Study of 275 Patients

BACKGROUND Decompressive spinal surgery patients have high expectations of recovering functionally, both at work and with leisurely activities. Affective disorders, such as depression or anxiety, are increasingly prevalent in this population and are associated with poorer baseline quality-of-life measures and worse postoperative outcomes. The study examined the results of affective disorders on self-reported recovery of baseline function (RBF) following decompressive spinal surgery. METHODS Medical records of 275 patients undergoing elective decompressive spinal surgery at a major academic institution were reviewed. There were 101 (36.7%) patients (with diagnosed anxiety or depression) in the affective disorder cohort (ADC) and 174 (63.6%) patients in the control cohort. The main outcome measure was self-reported RBF 3 months after surgery. Multivariate regression analysis was also used to determine whether affective disorders were a risk factor for poor RBF. RESULTS Baseline demographics, comorbidities, and perioperative variables between the two cohorts were similar, except for a higher proportion of females, more smokers, and longer length of stay in the ADC. On patient-reported outcome measures, the ADC had significantly decreased baseline scores and decreased improvement in scores over time. On univariate analysis, the ADC had significantly lower rates of RBF at 3 months after surgery. On regression analysis, affective disorders were an independent risk factors for poor RBF. CONCLUSIONS This study suggests that affective disorders are an independent risk factor for decreased recovery of baseline functionality after decompressive spinal surgery. Preoperatively identifying these patients could improve management of postoperative expectations and thereby improve surgical outcome.

Pedicle screw placement accuracy using ultra-low radiation imaging with image enhancement versus conventional fluoroscopy in minimally invasive transforaminal lumbar interbody fusion: an internally randomized controlled trial

OBJECTIVE A previous study found that ultra-low radiation imaging (ULRI) with image enhancement significantly decreases radiation exposure by roughly 75% for both the patient and operating room personnel during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) (p < 0.001). However, no clinical data exist on whether this imaging modality negatively impacts patient outcomes. Thus, the goal of this randomized controlled trial was to assess pedicle screw placement accuracy with ULRI with image enhancement compared with conventional, standard-dose fluoroscopy for patients undergoing single-level MIS-TLIF. METHODS An institutional review board-approved, prospective internally randomized controlled trial was performed to compare breach rates for pedicle screw placement performed using ULRI with image enhancement versus conventional fluoroscopy. For cannulation and pedicle screw placement, surgery on 1 side (left vs right) was randomly assigned to be performed under ULRI. Screws on the opposite side were placed under conventional fluoroscopy, thereby allowing each patient to serve as his/her own control. In addition to standard intraoperative images to check screw placement, each patient underwent postoperative CT. Three experienced neurosurgeons independently analyzed the images and were blinded as to which imaging modality was used to assist with each screw placement. Screw placement was analyzed for pedicle breach (lateral vs medial and Grade 0 [< 2.0 mm], Grade 1 [2.0-4.0 mm], or Grade 2 [> 4.0 mm]), appropriate screw depth (50%-75% of the vertebral bodys anteroposterior dimension), and appropriate screw angle (within 10° of the pedicle angle). The effective breach rate was calculated as the percentage of screws evaluated as breached > 2.0 mm medially or postoperatively symptomatic. RESULTS Twenty-three consecutive patients underwent single-level MIS-TLIF, and their sides were randomly assigned to receive ULRI. No patient had immediate postoperative complications (e.g., neurological decline, need for hardware repositioning). On CT confirmation, 4 screws that had K-wire placement and cannulation under ULRI and screw placement under conventional fluoroscopy showed deviations. There were 2 breaches that deviated medially but both were Grade 0 (< 2.0 mm). Similarly, 2 breaches occurred that were Grade 1 (> 2.0 mm) but both deviated laterally. Therefore, the effective breach rate (breach > 2.0 mm deviated medially) was unchanged in both imaging groups (0% using either ULRI or conventional fluoroscopy; p = 1.00). CONCLUSIONS ULRI with image enhancement does not compromise accuracy during pedicle screw placement compared with conventional fluoroscopy while it significantly decreases radiation exposure to both the patient and operating room personnel.