Anthony Sin

Impact of body habitus on fluoroscopic radiation emission during minimally invasive spine surgery

OBJECT Minimally invasive spine surgeries (MISSs) have gained immense popularity in the last few years. Concern about the radiation exposure has also been raised. The purpose of this study was to demonstrate the impact of body habitus on the radiation emission during various MISS procedures. The authors also aim to evaluate the effect the surgeons experience has on the amount of radiation exposure during MISS especially with regard to patient size. METHODS The authors conducted a retrospective analysis of 332 patients who underwent 387 MISS procedures performed at their institution from January 2010 to August 2013 by a single surgeon. The dose of radiation emission available from the fluoroscopic equipment was recorded from the electronic database. The authors analyzed mainly 3 procedure groups: microdiscectomy/decompression (MiDD, n=211) and transforaminal lumbar interbody fusion (TLIF) either with unilateral instrumentation (UnTLIF, n=106) or bilateral instrumentation (BiTLIF, n=70). The patients in each procedure group were divided into 6 categories based on the WHO criteria for obesity: underweight (body mass index [BMI]<18.50), normal (18.50-24.99), overweight (25.00-29.99), Class 1 obese (30.00-34.99), Class 2 obese (35.00- 39.99), and Class 3 obese (>40.00). RESULTS Patients who underwent BiTLIF had the highest median radiation exposure (113 mGy, SD 9.44), whereas microdiscectomy required minimal exposure (12.62 mGy, SD 2.75 mGy). There was a significant correlation between radiation emission and BMI of the patients during all MISS procedures (p<0.05). The median radiation exposure was substantially greater with larger patients (p≤0.001). In the analyses within the procedure groups, radiation exposure was found to be significantly high in patients who were severely obese (Class 2 and Class 3 obesity). The radiation emission was lower during the surgeries performed in 2013 than during those performed in 2010 especially in obese patients; however, this observation was not statistically significant. CONCLUSIONS Body habitus of the patients has a substantial impact on radiation emission during MISS. Severe obesity (BMI≥35) is associated with a significantly greater risk of radiation exposure compared with other weight categories. Surgical experience seems to be associated with lower radiation emission especially in cases in which patients have a higher BMI; however, further studies should be performed to examine this effect.

Gamma Knife stereotactic radiosurgery for intracranial metastases from conventionally radioresistant primary cancers: outcome analysis of survival and control of brain disease.

Objective: The aim of this study was to analyze our experience with stereotactic radiosurgery in the management of patients with brain metastases from radioresistant primary cancers. Methods: We retrospectively reviewed the clinical record of those patients for the outcome measures. All data were coded and entered into multivariate regression analysis for studying the relationship between survival and other variables. Results: Over a 48-month period, 31 patients received radiosurgery for brain metastases from renal cell carcinoma (n = 7), malignant melanoma (n = 14), or colon carcinoma (n = 10) at our institution. The followup ranged from 1–48 months (mean = 17 months). At the time of last followup, 11 patients (35.5%) were alive and 20 had died. Six deaths (30%) resulted from progressive brain disease while 14 patients died from progressive primary and/or extracranial metastatic disease. Mean survival from radiosurgery was 12 months (95% CI, 7–17) and the median survival was 7 months. The 1 and 2 year actuarial survival rates were 32.5 ± 1% and 12.2 ± 1% respectively. The overall survival was directly related to tumor control time (P <0.001) and inversely to the number of metastases (P = 0.031). Conclusion: Gamma Knife® stereotactic radiosurgery for intracranial metastases from conventionally radioresistant primary cancers is a safe and effective method to provide better local control of the brain disease and improve survival time.

Cumulative survival analysis of patients with spinal myxopapillary ependymomas in the first 2 decades of life

OBJECT Reports of myxopapillary ependymomas (MPEs) of the spinal cord in pediatric patients are scarce. In the literature, various authors have shared their experiences with small groups of patients, which makes it difficult to create a consensus regarding the treatment approach for spinal MPEs in young patients. The aim of this study was to perform a survival analysis of patients in the first 2 decades of life whose cases were selected from the published studies, and to examine the influence of various factors on outcomes. METHODS A comprehensive search of studies published in English was performed on PubMed. Patients whose age was ≤ 20 years were included for integrative analysis. Information about age, treatment characteristics, critical events (progression, recurrence, and death), time to critical events, and follow-up duration was recorded. The degree of association of the various factors with the survival outcome was calculated by using Kaplan-Meier estimator and Cox proportional hazard model techniques. RESULTS A total of 95 patients were included in the analysis. The overall rate of recurrence (RR) was 34.7% (n = 33), with a median time to recurrence of 36 months (range 2-100 months). Progression-free survival (PFS) and overall survival rates at 5 years were 73.7% and 98.9%, respectively. Addition of radiotherapy (RT) following resection significantly improved PFS (log-rank test, p = 0.008). In patients who underwent subtotal resection (STR), administering RT (STR + RT) improved outcome with the lowest failure rates (10.3%), superior to patients who underwent gross-total resection (GTR) alone (RR 43.1%; log-rank test, p < 0.001). Addition of RT to patients who underwent GTR was not beneficial (log-rank test, p = 0.628). In patients who had disseminated tumor at presentation, adjuvant RT controlled the disease effectively. High-dose RT (≥ 50 Gy) did not change PFS (log-rank test, p = 0.710). CONCLUSIONS Routine inclusion of RT in the treatment protocol for spinal MPEs in young patients should be considered. Complete resection is always the goal of tumor resection. However, when complete resection does not seem to be possible in complex lesions, RT should be used as an adjunct to avoid aggressive resection and to minimize inadvertent injury to the surrounding neural tissues. High-dose RT (≥ 50 Gy) did not provide additional survival benefits, although this association needs to be evaluated by prospective studies.

Adopting 540-degree fusion to correct cervical kyphosis

BACKGROUND Two cases of severe cervical spine kyphotic deformity resulting from late effects of infection were successfully corrected by combined anterior and posterior instrumentations in a single operative sitting. CASE DESCRIPTION Case 1 is a 43-year-old man who developed severe cervical kyphosis from C5-6 discitis over a few months despite long-term antibiotic therapy. He was neurologically intact except for severe neck pain and obvious deformity. Case 2 is a 40-year-old woman who had a previous wound infection five years before presentation. There was gradual worsening of swan neck deformity at the C2-3 and C5-6 levels with some spinal cord compression worsening her baseline myelopathy. The patients were placed and maintained in cervical traction on the Stryker frame for the duration of the procedure. Both cases required anterior approach initially to achieve some release of dense scar tissue using a high-speed drill. The wounds were then closed and patients were rotated to the prone position for further release of fused bony elements, including the facets. Lateral mass screws and plates were placed. In Case 2, additional instrument to the occipital was performed to stabilize the C2 using a U-shaped cervical rod. Once adequate reduction had been achieved, the patients were rotated back to supine position for further corpectomy and fibular construct fusion with plates. CONCLUSION In cases of severe kyphotic deformity complicating infectious vertebral destruction, the spinal alignment can be achieved safely by a multi-step technique combining the anterior as well as posterior surgical approaches.

Iatrogenic splenic injury during anterior thoracolumbar spinal surgery : Case report

The proximity of major abdominal structures encountered in the approach for an anterior thoracolumbar spinal operation makes patients vulnerable to potential intraoperative complications. The spleen, in particular, can be easily injured during manipulation or from being under retractors for a number of hours, although it is a rarely reported phenomenon in the literature. The authors report on a 52-year-old man who suffered a spleen laceration following anterior L1-2 corpectomy and fusion for osteomyelitis of the lumbar spine. The patient required an emergency splenectomy, but he made a full recovery.

Adolescent idiopathic scoliosis: risk factors for complications and the effect of hospital volume on outcomes

OBJECTIVE Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis. Limited literature exists defining risk factors associated with outcomes during initial hospitalization in these patients. In this study, the authors investigated patient demographics, clinical and hospital characteristics impacting short-term outcomes, and costs in adolescent patients undergoing surgical deformity correction for idiopathic scoliosis. Additionally, the authors elucidate the impact of hospital surgical volume on outcomes for these patients. METHODS Using the National Inpatient Sample database and appropriate International Classification of Diseases, 9th Revision codes, the authors identified adolescent patients (10-19 years of age) undergoing surgical deformity correction for idiopathic scoliosis during 2001-2014. For national estimates, appropriate weights provided by the Agency of Healthcare Research and Quality were used. Multivariable regression techniques were employed to assess the association of risk factors with discharge disposition, postsurgical neurological complications, length of hospital stay, and hospitalization costs. RESULTS Overall, 75,106 adolescent patients underwent surgical deformity correction. The rates of postsurgical complications were estimated at 0.9% for neurological issues, 2.8% for respiratory complications, 0.8% for cardiac complications, 0.4% for infections, 2.7% for gastrointestinal complications, 0.1% for venous thromboembolic events, and 0.1% for acute renal failure. Overall, patients stayed at the hospital for an average of 5.72 days (median 5 days) and on average incurred hospitalization costs estimated at

Placement of C1 Pedicle Screws Using Minimal Exposure: Radiographic, Clinical, and Literature Validation

54,997 (median

Medicare payment data for spine reimbursement; important but flawed data for evaluating utilization of resources.

47,909). As compared with patients at low-volume centers (≤ 50 operations/year), those undergoing surgical deformity correction at high-volume centers (> 50/year) had a significantly lower likelihood of an unfavorable discharge (discharge to rehabilitation) (OR 1.16, 95% CI 1.03-1.30, p = 0.016) and incurred lower costs (mean

A Cost-Effectiveness Analysis of the Integration of Robotic Spine Technology in Spine Surgery

33,462 vs

Minimally invasive spine surgery in the pediatric and adolescent population: A case series

56,436, p < 0.001) but had a longer duration of stay (mean 6 vs 5.65 days, p = 0.002). In terms of neurological complications, no significant differences in the odds ratios were noted between high- and low-volume centers (OR 1.23, 95% CI 0.97-1.55, p = 0.091). CONCLUSIONS This study provides insight into the clinical characteristics of AIS patients and their postoperative outcomes following deformity correction as they relate to hospital volume. It provides information regarding independent risk factors for unfavorable discharge and neurological complications following surgery for AIS. The proposed estimates could be used as an adjunct to clinical judgment in presurgical planning, risk stratification, and cost containment.