Risk for surgical complications after previous stereotactic body radiotherapy of the spine

OBJECT

Stereotactic body radiotherapy (SBRT) for vertebral metastases has emerged as a promising technique, offering high rates of symptom relief and local control combined with low risk of toxicity. Nonetheless, local failure or vertebral instability may occur after spine SBRT, generating the need for subsequent surgery in the irradiated region. This study evaluated whether there is an increased incidence of surgical complications in patients previously treated with SBRT at the index level.

METHODS

Based upon a retrospective international database of 704 cases treated with SBRT for vertebral metastases, 30 patients treated at 6 different institutions were identified who underwent surgery in a region previously treated with SBRT.

RESULTS

Thirty patients, median age 59 years (range 27-84 years) underwent SBRT for 32 vertebral metastases followed by surgery at the same vertebra. Median follow-up time from SBRT was 17 months. In 17 cases, conventional radiotherapy had been delivered prior to SBRT at a median dose of 30 Gy in median 10 fractions. SBRT was administered with a median prescription dose of 19.3 Gy (range 15-65 Gy) delivered in median 1 fraction (range 1-17) (median EQD2/10 = 44 Gy). The median time interval between SBRT and surgical salvage therapy was 6 months (range 1-39 months). Reasons for subsequent surgery were pain (n = 28), neurological deterioration (n = 15) or fracture of the vertebral body (n = 13). Open surgical decompression (n = 24) and/or stabilization (n = 18) were most frequently performed; Five patients (6 vertebrae) were treated without complications with vertebroplasty only. Increased fibrosis complicating the surgical procedure was explicitly stated in one surgical report. Two durotomies occurred which were closed during the operation, associated with a neurological deficit in one patient. Median blood loss was 500 ml, but five patients had a blood loss of more than 1 l during the procedure. Delayed wound healing was reported in two cases. One patient died within 30 days of the operation.

CONCLUSION

In this series of surgical interventions following spine SBRT, the overall complication rate was 19%, which appears comparable to primary surgery without previous SBRT. Prior spine SBRT does not appear to significantly increase the risk of intra- and post-surgical complications.

Evaluation of outcomes after stereotactic radiosurgery for pilocytic astrocytoma

Pilocytic astrocytomas are rare intracranial gliomas that are typically treated with surgical extirpation. Our aim was to report the radiologic and clinical outcomes of patients treated with stereotactic radiosurgery (SRS) for pilocytic astrocytoma in the primary and salvage setting. Patients with pilocytic astrocytoma treated at a single institution with SRS from 1990 to 2015 were reviewed. Patient, disease, and treatment characteristics were collected and overall survival, local control, and toxicity were evaluated. Twenty-eight consecutive patients (12 females and 16 males) with a median age of 17.4 years at SRS were identified. Overall, 46% of patients were treated with SRS as part of the initial treatment course after biopsy or subtotal resection, and the remainder as a salvage therapy. The most common location was the cerebellum (28%) followed by brainstem and basal ganglia (21 and 18%, respectively). Four patients received prior external beam radiation therapy (14%). Median tumor volume was 1.84 cc (0.19-15.94 cc), and 39% had a cystic component at SRS. Prescription dose ranged from 4 to 20 Gy (median 16 Gy) to a median isodose line of 50% (range 30-100%). With a median follow-up of 5.2 years (0.3-17.1 years), all patients remained alive at last follow-up. Two patients demonstrated evidence of local radiographic progression at last follow-up (7%). No toxicity could be directly attributed to SRS. In this SRS series, durable tumor control was achieved in 93% of patients with pilocytic astrocytoma, although continued follow up will be important giving the natural history of this disease. As demonstrated, SRS is an appropriate technique in the primary and recurrent treatment of pilocytic astrocytoma that offers favorable disease control and infrequent clinical toxicity.

Vertebral compression fractures after stereotactic body radiation therapy: a large, multi-institutional, multinational evaluation

OBJECTIVE

The purpose of this study was to identify factors contributing to an increased risk for vertebral compression fracture (VCF) following stereotactic body radiation therapy (SBRT) for spinal tumors.

METHODS

A total of 594 tumors were treated with spinal SBRT as primary treatment or re-irradiation at 8 different institutions as part of a multi-institutional research consortium. Patients underwent LINAC-based, image-guided SBRT to a median dose of 20 Gy (range 8–40 Gy) in a median of 1 fraction (range 1–5 fractions). Median patient age was 62 years. Seventy-one percent of tumors were osteolytic, and a preexisting vertebral compression fracture (VCF) was present in 24% of cases. Toxicity was assessed following treatment. Univariate and multivariate analyses were performed using a logistic regression method to determine parameters predictive for post-SBRT VCF.

RESULTS

At a median follow-up of 10.1 months (range 0.03–57 months), 80% of patients had local tumor control. At the time of last imaging follow-up, at a median of 8.8 months after SBRT, 3% had a new VCF, and 2.7% had a progressive VCF. For development of any (new or progressive) VCF following SBRT, the following factors were predictive for VCF on univariate analysis: short interval from primary diagnosis to SBRT (less than 36.8 days), solitary metastasis, no additional bone metastases, no prior chemotherapy, preexisting VCF, no MRI used for target delineation, tumor volume of 37.3 cm3 or larger, equivalent 2-Gy-dose (EQD2) tumor of 41.8 Gy or more, and EQD2 spinal cord Dmax of 46.1 Gy or more. Preexisting VCF, solitary metastasis, and prescription dose of 38.4 Gy or more were predictive on multivariate analysis. The following factors were predictive of a new VCF on univariate analysis: solitary metastasis, no additional bone metastases, and no MRI used for target delineation. Presence of a solitary metastasis and lack of MRI for target delineation remained significant on multivariate analysis.

CONCLUSIONS

A VCF following SBRT is more likely to occur following treatment for a solitary spinal metastasis, reflecting a more aggressive treatment approach in patients with adequately controlled systemic disease. Higher prescription dose and a preexisting VCF also put patients at increased risk for post-SBRT VCF. In these patients, pre-SBRT cement augmentation could be considered to decrease the risk of subsequent VCF.

Clinical practice of image-guided spine radiosurgery--results from an international research consortium

Background

Spinal radiosurgery is a quickly evolving technique in the radiotherapy and neurosurgical communities. However, the methods of spine radiosurgery have not been standardized. This article describes the results of a survey about the methods of spine radiosurgery at five international institutions.

Methods

All institutions are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided radiosurgery. The questionnaire consisted of 75 items covering all major steps of spine radiosurgery.

Results

Strong agreement in the methods of spine radiosurgery was observed. In particular, similarities were observed with safety and quality assurance playing an important role in the methods of all institutions, cooperation between neurosurgeons and radiation oncologists in case selection, dedicated imaging for target- and organ-at-risk delineation, application of proper safety margins for the target volume and organs-at-risk, conformal planning and precise image-guided treatment delivery, and close clinical and radiological follow-up. In contrast, three major areas of uncertainty and disagreement were identified: 1) Indications and contra-indications for spine radiosurgery; 2) treatment dose and fractionation and 3) tolerance dose of the spinal cord.

Conclusions

Results of this study reflect the current practice of spine radiosurgery in large academic centers. Despite close agreement was observed in many steps of spine radiosurgery, further research in form of retrospective and especially prospective studies is required to refine the details of spinal radiosurgery in terms of safety and efficacy.

Child and adolescent fast-food choice and the influence of calorie labeling: a natural experiment

OBJECTIVE

Obesity is an enormous public health problem and children have been particularly highlighted for intervention. Of notable concern is the fast-food consumption of children . However, we know very little about how children or their parents make fast-food choices, including how they respond to mandatory calorie labeling. We examined children's and adolescents' fast-food choice and the influence of calorie labels in low-income communities in New York City (NYC) and in a comparison city (Newark, NJ).

DESIGN

Natural experiment: Survey and receipt data were collected from low-income areas in NYC, and Newark, NJ (as a comparison city), before and after mandatory labeling began in NYC. Study restaurants included four of the largest chains located in NYC and Newark: McDonald's, Burger King, Wendy's and Kentucky Fried Chicken.

SUBJECTS

A total of 349 children and adolescents aged 1-17 years, who visited the restaurants with their parents (69%) or alone (31%) before or after labeling was introduced. In total, 90% were from racial or ethnic minority groups.

RESULTS

We found no statistically significant differences in calories purchased before and after labeling; many adolescents reported noticing calorie labels after their introduction (57% in NYC) and a few considered the information when ordering (9%). Approximately 35% of adolescents ate fast food six or more times per week and 72% of adolescents reported that taste was the most important factor in their meal selection. Adolescents in our sample reported that parents have some influence on their meal selection.

CONCLUSIONS

Adolescents in low-income communities notice calorie information at similar rates as adults, although they report being slightly less responsive to it than adults. We did not find evidence that labeling influenced adolescent food choice or parental food choices for children in this population.

Gamma Knife radiosurgery for trigeminal neuralgia: the impact of magnetic resonance imaging–detected vascular impingement of the affected nerve

Object

Trigeminal neuralgia is believed to be related to vascular compression of the affected nerve. Radiosurgery has been shown to be reasonably effective for treatment of medically refractory trigeminal neuralgia. This study explores the rate of occurrence of MR imaging–demonstrated vascular impingement of the affected nerve and the extent to which vascular impingement affects pain relief in a population of trigeminal neuralgia patients undergoing Gamma Knife radiosurgery (GKRS).

Methods

The authors performed a retrospective analysis of 106 cases involving patients treated for typical trigeminal neuralgia using GKRS. Patients with or without single-vessel impingement on CISS MR imaging sequences and with no previous surgery were included in the study. Pain relief was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at the last follow-up. Degree of impingement, nerve diameter preand post-impingement, isocenter placement, and dose to the point of maximum impingement were evaluated in relation to the improvement of BNI score.

Results

The overall median follow-up period was 31 months. Overall, a BNI pain score of 1 was achieved in 59.4% of patients at last follow-up. Vessel impingement was seen in 63 patients (59%). There was no significant difference in pain relief between those with and without vascular impingement following GKRS (p > 0.05).

In those with vascular impingement on MR imaging, the median fraction of vessel impingement was 0.3 (range 0.04–0.59). The median dose to the site of maximum impingement was 42 Gy (range 2.9–79 Gy). Increased dose (p = 0.019) and closer proximity of the isocenter to the site of maximum vessel impingement (p = 0.012) correlated in a statistically significant fashion with improved BNI scores in those demonstrating vascular impingement on the GKRS planning MR imaging

Conclusions

Vascular impingement of the affected nerve was seen in the majority of patients with trigeminal neuralgia. Overall pain relief following GKRS was comparable in those with and without evidence of vascular compression on MR imaging. In subgroup analysis of those with MR imaging evidence of vessel impingement of the affected trigeminal nerve, pain relief correlated with a higher dose to the point of contact between the impinging vessel and the trigeminal nerve. Such a finding may point to vascular changes affording at least some degree of relief following GKRS for trigeminal neuralgia.

Can additional experienced staff reduce emergency medical admissions?

BACKGROUND

Increases in emergency medical admissions are placing a strain upon hospitals throughout the world. The aim of the study was to evaluate the effect of a new post, the "A&E physician", upon emergency medical admissions to a hospital.

METHODS

For six months the A&E physician workload was audited and a randomised controlled comparison undertaken. Days were randomised to "A&E physician present" or "A&E physician absent". The A&E physician recorded details of all patients referred for medical admission, any intervention made, and their disposal from A&E. Routine hospital data compared the mean daily number of medical admissions, non-medical admissions, and referrals to other hospitals.

RESULTS

124 days were randomised: 59 to A&E physician present, 65 to A&E physician absent. The A&E physician received 581 referrals and intervened in the management of 142 (24%). Of these, 80 were discharged home, apparently saving 1.4 admissions per day. However, randomised comparison showed that presence of the A&E physician was associated with a reduction of only 0.7 medical admissions per day (95% CI -1.7 to 3.2, p = 0.561), and an increase of 1.1 non-medical admissions (95% CI -0.2 to 2.3, p = 0.09) and 0.3 transfers to other hospitals per day (95% CI zero to 0.6, p = 0.09). Overall, hospital admissions were increased by 0.9 per day when the A&E physician was present (95% CI -1.8 to 3.6, p = 0.5).

CONCLUSION

Despite receiving many referrals and discharging a substantial proportion of these patients home, the A&E physician did not significantly change emergency medical admissions and may have increased admissions to other specialties.

Prevention of microvascular thrombosis with short-term infusion of human tissue-type plasminogen activator

A locally active thrombolytic agent, human tissue-type plasminogen activator (t-PA), given over a finite time period (24 hours) by local infusion, maintains long-term microvascular patency (7 days) in a proven thrombosis model using an arterial inversion graft in the rabbit model. Thirteen rabbits in the control group and 16 rabbits in the experimental group underwent an arterial inversion graft followed by continuous infusion (24 hours) with human tissue-type plasminogen activator (experimental) or normal saline (control). No significant clinical bleeding or alteration of coagulation parameters was noted in hematologic studies in both experimental and control groups. Scanning electron microscopy of the postoperative human tissue-type plasminogen activator-perfused arteries suggests an interaction of the human tissue-type plasminogen activator with specific platelet receptors in reversing microvascular thrombosis by decreasing or preventing further platelet aggregation and adhesion. Human tissue-type plasminogen activator infused locally for a finite period (24 hours) allows adequate time for platelet metamorphosis to occur in converting a thrombogenic to a nonthrombogenic vessel surface. The clinical ramifications in preventing or reversing microvascular thrombosis in free-tissue transfers and replantation surgery are apparent. Further study in this area will enhance our understanding of the pathogenesis and prevention of microvascular thrombosis.

Human recombinant tissue type plasminogen activator and its effect on microvascular thrombosis in the rabbit

A new potent thrombolytic agent, human tissue type plasminogen activator (t-PA), has become available for study through recombinant DNA technology. In this series of experiments, we have tested t-PA in a reliable microvascular thrombosis model previously developed in our laboratory. Its action in preventing thrombus formation and lysing fresh clot by direct local infusion and systemic infusion was tested. The results revealed that t-PA was able to keep locally infused vessels open for 4 hours and reopen them after they were allowed to clot in 100 percent of the animals tested. Those vessels exposed only to systemic levels of t-PA achieved by the same local infusion remained thrombosed and were unaffected. Laboratory studies showed no evidence of activation of the systemic lytic state or alteration in coagulation parameters. t-PA has proved to be a protein with characteristics that make it attractive for use in microvascular surgery. The results suggest that further research may lead the way toward clinical use.

Carcinoma of the female urethra: combined iridium Ir 192 interstitial and external beam radiotherapy

Three female patients (mean age 55) with carcinoma of the urethra were treated with combined external beam irradiation (4,000 to 5,000 rads) and interstitial irradiation with iridium Ir 192 (2,700 to 3,000 rads) applied with a modified Syed-Neblett template. Two patients are alive with no evidence of disease at 27 and 37 months. One patient died of a second primary tumor at 30 months, without histologic evidence of the original urethral neoplasm. No patient had significant complications of therapy. This treatment regimen is effective for selected women with urethral carcinoma.