Machine learning approach for the development of a crucial tool in suicide prevention: The Suicide Crisis Inventory-2 (SCI-2) Short Form.

The Suicide Crisis Syndrome (SCS) describes a suicidal mental state marked by entrapment, affective disturbance, loss of cognitive control, hyperarousal, and social withdrawal that has predictive capacity for near-term suicidal behavior. The Suicide Crisis Inventory-2 (SCI-2), a reliable clinical tool that assesses SCS, lacks a short form for use in clinical settings which we sought to address with statistical analysis. To address this need, a community sample of 10,357 participants responded to an anonymous survey after which predictive performance for suicidal ideation (SI) and SI with preparatory behavior (SI-P) was measured using logistic regression, random forest, and gradient boosting algorithms. Four-fold cross-validation was used to split the dataset in 1,000 iterations. We compared rankings to the SCI-Short Form to inform the short form of the SCI-2. Logistic regression performed best in every analysis. The SI results were used to build the SCI-2-Short Form (SCI-2-SF) utilizing the two top ranking items from each SCS criterion. SHAP analysis of the SCI-2 resulted in meaningful rankings of its items. The SCI-2-SF, derived from these rankings, will be tested for predictive validity and utility in future studies.

Impact of the Abbreviated Suicide Crisis Syndrome Checklist on Clinical Decision Making in the Emergency Department.

Objective: The suicide crisis syndrome (SCS), an acute negative affect state predictive of near-term suicidal behavior, is currently under review for inclusion as a suicide-specific diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM). While the predictive validity of the SCS for near-term suicidal behavior is well documented, its real-world clinical utility has yet to be evaluated. As such, this study evaluated how implementation of a novel assessment tool, the Abbreviated SCS Checklist (A-SCS-C), into the electronic medical records (EMRs) influenced disposition decisions in the emergency departments (EDs) of a large urban health system.Methods: Logistic regression analyses evaluated the impact of SCS diagnosis on 212 admission/discharge decisions after accounting for chief complaints of suicidal ideation (SI), suicidal behavior (SB), and psychosis/agitation.Results: The A-SCS-C was concordant with 86.9% of all non-psychotic disposition decisions. In multivariable analysis, the A-SCS-C had an adjusted odds ratio (AOR) of 65.9 (95% confidence interval: 18.79-231.07) for inpatient admission, whereas neither suicidal ideation nor behavior was a significant predictor. The effect size remained very high in 3 sensitivity analyses, the first using information from a different section of the EMR, the second in patients younger than 18 years, and the third in males and females separately (AORs > 30).Conclusions: SCS diagnosis, when implemented in ED EMRs alongside SI and SB, was strongly predictive of clinician decision making with regard to admission/discharge, particularly in non-psychotic patients, while SI and SB were noncontributory. Overall, our results show that the SCS, as a diagnostic entity, demonstrates robust clinical utility and may reduce the limitations of relying on self-reported SI as a primary basis of suicide risk assessment.

Quality indicators for hyperthermia treatment: Italian survey analysis.

AIM: Nowadays, no Quality Indicators (QI) have been proposed for Hyperthermia treatments. Starting from radiotherapy experience, the aim of this work is to adapt radiotherapy indicators to Hyperthermia and to propose a new specific set of QI in Hyperthermia field. MATERIAL AND METHODS: At first, radiotherapy quality indicators published in literature have been adapted to hyperthermia setting. Moreover, new specific indicators for the treatment of hyperthermia have been defined. To obtain the standard reference values of quality indicators, a questionnaire was sent to 7 Italian hyperthermia Institutes with a list of questions on physical and clinical hyperthermia treatment in order to highlight the different therapeutic approaches. RESULTS: Three structure, five process and two outcome QI were selected. It has been possible to adapt seven indicators from radiotherapy, while three indicators have been defined as new specific indicators for hyperthermia. Average values used as standard reference values have been obtained and proposed. CONCLUSION: The survey performed on 7 Italian centres allowed to derive the standard reference value for each indicator. The proposed indicators are available to be investigated and applied by a larger number of Institutes in which hyperthermia treatment is performed in order to monitor the operational procedures and to confirm or modify the reference standard value derived for each indicator.

Quantitative analysis of cerebrospinal fluid dynamics at phase contrast cine-MRI: predictivity of neurosurgical "Shunt" responsiveness in patients with idiopathic normal pressure hydrocephalus.

BACKGROUND: Aqueductal stroke volume (ACSV) measured by phase-contrast cine (PCC)-MRI has been proposed with controversy as a tool for the selection of patients with normal pressure hydrocephalus (NPH) as candidates for shunt-surgery. The aim of this study was to assess if PCC-MRI scan measurements of ACSV could select properly these patients. METHODS: We retrospectively reviewed charts and MRI of 38 shunted patients (72.16±6.16 years). ACSV measurements were performed 7-30 days before shunt and at the first and sixth months after surgery. Normally distributed variables were compared in the two groups (improved/unimproved) by t-test for baseline values and with repeated measures analysis of variance. RESULTS: Twenty-six patients (68,4%) improved after VPS (mean time of symptom onset was 8.15±7.19 months). Mean preoperative ACSV value was 271.85±143.03, which decreased by 21.6% (mean 213±125.14) at the first month and 40.3% sixth months after VPS (mean 162.15±91.5). Twelve patients (31.6%) did not improve (mean time of symptom onset was 29±5.62 months). Mean preoperative ACSV value was 79.83±31.24, decreased to 8.7% (mean 72.83±28.66) at first month after VPS. 21.2% (mean 62.83±31.12) after six months. We found statistical difference between preoperative ACSV of improved and unimproved patients (P<0.01), onset time of symptoms (P<0.01) and the changes in ACSV after one and six months in both groups (P<0.001). CONCLUSIONS: ACSV is useful to stratify patients with NPH after surgery (improved /not improved) suggesting to proceed with serial ACSV measurements before deciding treatment.

Ureasil Organic-Inorganic Hybrid as a Potential Carrier for Combined Delivery of Anti-Inflammatory and Anticancer Drugs.

There continues to be a need to develop controlled-release systems loaded with multiple drugs with distinct pharmacological activities, such as anti-inflammatory and anticancer effects, which are able to provide the desired release of each drug, as a function of time. To this end, an elegant strategy was developed for the incorporation, in a one-step process, of the anti-inflammatory drug naproxen (NAP) and the anticancer drug 5-fluorouracil (5FU) into a ureasil organic-inorganic hybrid matrix. A ureasil-poly(oxyalkylene) (UPEO) matrix was prepared using a sol-gel route to obtain a versatile dual-drug delivery system. Small-angle X-ray scattering (SAXS) measurements and Fourier transform infrared spectroscopy (FTIR) demonstrated that the UPEO network is preserved upon loading with the two drugs NAP and 5FU. There was excellent agreement between the macroscopic swelling behavior (water uptake) and surface wettability (determined using contact angle measurements), with this behavior being closely correlated with the release profiles and playing an important role in the sustained delivery of both drugs from the hybrid matrix. The amounts of both drugs released simultaneously could be finely controlled by adjusting the pH of the aqueous medium, with the release presenting stimulus-responsive behavior. In an aqueous PBS medium, the dual-UPEO-release system presented excellent potential as a vehicle for the release of the water-soluble 5FU and water-insoluble NAP drugs, at identical rates, using a single carrier. This novel and adjustable dual-drug delivery UPEO system is a promising hybrid material carrier with the ability to simultaneously incorporate a wide range of therapeutic agents for the treatment of various diseases, including cancers.

Impact of a rectal and bladder preparation protocol on prostate cancer outcome in patients treated with external beam radiotherapy.

PURPOSE AND OBJECTIVE: To test the hypothesis that a rectal and bladder preparation protocol is associated with an increase in prostate cancer specific survival (PCSS), clinical disease free survival (CDFS) and biochemical disease free survival (BDFS). PATIENTS AND METHODS: From 1999 to 2012, 1080 prostate cancer (PCa) patients were treated with three-dimensional conformal radiotherapy (3DCRT). Of these patients, 761 were treated with an empty rectum and comfortably full bladder (RBP) preparation protocol, while for 319 patients no rectal/bladder preparation (NRBP) protocol was adopted. RESULTS: Compared with NRBP patients, patients with RBP had significantly higher BDFS (64% vs 48% at 10 years, respectively), CDFS (81% vs 70.5% at 10 years, respectively) and PCSS (95% vs 88% at 10 years, respectively) (log-rank test p < 0.001). Multivariate analysis (MVA) indicated for all treated patients and intermediate high-risk patients that the Gleason score (GS) and the rectal and bladder preparation were the most important prognostic factors for PCSS, CDFS and BDFS. With regard to high- and very high-risk patients, GS, RBP, prostate cancer staging and RT dose were predictors of PCSS, CDFS and BDFS in univariate analysis (UVA). CONCLUSION: We found strong evidence that rectal and bladder preparation significantly decreases biochemical and clinical failures and the probability of death from PCa in patients treated without daily image-guided prostate localization, presumably since patients with RBP are able to maintain a reproducibly empty rectum and comfortably full bladder across the whole treatment compared with NRPB patients.

Quality indicators in the intensity modulated/image-guided radiotherapy era.

PURPOSE: To propose new Quality Indicators (QIs) for the Intensity Modulated(IMRT)/Image-Guided(IGRT) Radiotherapy techniques. MATERIALS AND METHODS: Two structure, 10 process and 2 outcome QIs were elaborated. A working group including Radiation Oncologist, Medical Physicist and Radiation Technologists was made up. A preliminary set of indicators was selected on the basis of evidenced critical issues; the criteria to identify more relevant and specific QIs for IMRT/IGRT were defined; structure, process and outcome QIs were defined. The elaborated indicators were tested in four Italian Radiotherapy Centers. RESULTS: Fourteen indicators were proposed. Seven indicators were completely new while a new standard is proposed for four indicators based on Validation Centers (VC) data. No change was reported for 3 indicators. The indicators were applied in the four VC. The VC considered were able to respect all indicators except indicator 2 for one Center. DISCUSSION AND CONCLUSION: QIs may provide useful measures of workload and service performances.

NOD-SCID mice irradiation with medical accelerators: Dosimetric and radiobiological results.

PURPOSE: Preclinical studies normally requires dedicated instruments due to the small anatomical scales involved, but the possibility of using clinical devices for this purpose may be of economical, scientific and translational interest. In the present work the accurate description of treatment planning, dosimetric results, radiotoxicity and tumor response of the irradiation of NOD-SCID mice were presented. Two medical linear accelerators, TrueBeam STx and Tomotherapy Hi-ART, were compared. NOD-SCID mice irradiation with Tomotherapy is a novelty, as well as the comparison of different irradiation techniques, devices and dose fractionations. METHODS: Human derived glioblastoma multiforme neurospheres were injected in immunocompromised NOD-SCID mice to establish xenograft models. Mice were anaesthetized and placed in a plexiglas cage pieboth to perform CT scan for treatment planning purposes and for the irradiation. Three fractionation schedules were evaluated: 4Gy/1 fraction, 4Gy/2 fractions and 6Gy/3 fractions. Tomotherapy planning parameters, the presence of a bolus layer and the irradiation time were reported. After irradiation, mice were examined daily and sacrificed when they showed signs of suffering or when tumor volume reached the established endpoint. Outcomes regarding both radiotoxicity and tumor response were evaluated comparing irradiated mice as respect to their controls. RESULTS: Survival analysis showed that Tomotherapy irradiation with 6Gy/3 fractions with a bolus layer prolong mice survival (log-rank test, p<0.02). Tumor volume and mice survival were significantly different in irradiated xenografts as compared to their controls (t-test, p<0.03; log-rank, p<0.05). CONCLUSION: The radiobiological potential of Tomotherapy in inducing tumor growth stabilization is demonstrated.

Technical considerations in transforaminal endoscopic spine surgery at the thoracolumbar junction: report of 3 cases.

OBJECTIVE In this study the authors describe the technical considerations and feasibility of transforaminal discectomy and foraminoplasty for the treatment of lumbar radiculopathy in patients who have herniated discs at the thoracolumbar junction. METHODS After institutional review board approval, charts from 3 consecutive patients with lumbar radiculopathy and T12-L1 herniated discs who underwent endoscopic procedures between 2006 and 2014 were reviewed. RESULTS Consecutive cases (n = 1316) were reviewed to determine the incidence and success of surgery performed at the T12-L1 level. Only 3 patients (0.23%) treated with endoscopic surgery for their herniated discs had T12-L1 herniated discs; the rest were lumbar or lumbosacral herniations. For patients with T12-L1 disc herniations, the average preoperative visual analog scale score was 8.3 (indicated in the questionnaire as describing severe and constant pain). The average 1-year postoperative visual analog scale score was 1.7 (indicated in the questionnaire as mild and intermittent pain). CONCLUSIONS Transforaminal endoscopic discectomy and foraminotomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a thoracolumbar disc herniation.

Is there still a role for computed tomography and bone scintigraphy in prostate cancer staging? An analysis from the EUREKA-1 database.

PURPOSE: According to the current guidelines, computed tomography (CT) and bone scintigraphy (BS) are optional in intermediate-risk and recommended in high-risk prostate cancer (PCa). We wonder whether it is time for these examinations to be dismissed, evaluating their staging accuracy in a large cohort of radical prostatectomy (RP) patients. METHODS: To evaluate the ability of CT to predict lymph node involvement (LNI), we included 1091 patients treated with RP and pelvic lymph node dissection, previously staged with abdomino-pelvic CT. As for bone metastases, we included 1145 PCa patients deemed fit for surgery, previously staged with Tc-99m methylene diphosphonate planar BS. RESULTS: CT scan showed a sensitivity and specificity in predicting LNI of 8.8 and 98 %; subgroup analysis disclosed a significant association only for the high-risk subgroup of 334 patients (P 0.009) with a sensitivity of 11.8 % and positive predictive value (PPV) of 44.4 %. However, logistic multivariate regression analysis including preoperative risk factors excluded any additional predictive ability of CT even in the high-risk group (P 0.40). These data are confirmed by ROC curve analysis, showing a low AUC of 54 % for CT, compared with 69 % for Partin tables and 80 % for Briganti nomogram. BS showed some positivity in 74 cases, only four of whom progressed, while 49 patients with negative BS progressed during their follow-up, six of them immediately after surgery. CONCLUSIONS: According to our opinion, the role of CT and BS should be restricted to selected high-risk patients, while clinical predictive nomograms should be adopted for the surgical planning.

Could machine learning improve the prediction of pelvic nodal status of prostate cancer patients? Preliminary results of a pilot study.

We tested and compared performances of Roach formula, Partin tables and of three Machine Learning (ML) based algorithms based on decision trees in identifying N+ prostate cancer (PC). 1,555 cN0 and 50 cN+ PC were analyzed. Results were also verified on an independent population of 204 operated cN0 patients, with a known pN status (187 pN0, 17 pN1 patients). ML performed better, also when tested on the surgical population, with accuracy, specificity, and sensitivity ranging between 48-86%, 35-91%, and 17-79%, respectively. ML potentially allows better prediction of the nodal status of PC, potentially allowing a better tailoring of pelvic irradiation.

Transforaminal endoscopic treatment of lumbar radiculopathy after instrumented lumbar spine fusion.

BACKGROUND: Transforaminal endoscopic discectomy and foraminotomy is a well-described minimally invasive technique for surgically treating lumbar radiculopathy caused by a herniated disc and foraminal narrowing. OBJECTIVE: To describe the technique and feasibility of transforaminal foraminoplasty for the treatment of lumbar radiculopathy in patients who have already undergone instrumented spinal fusion. STUDY DESIGN: Retrospective study. SETTING: Hospital and ambulatory surgery center METHODS: After Institutional Review Board approval, charts from 18 consecutive patients with lumbar radiculopathy and instrumented spinal fusions who underwent endoscopic procedures between 2008 and 2013 were reviewed. RESULTS: The average pain relief one year postoperatively was reported to be 67.0%, good results as defined by MacNab. The average preoperative VAS score was 9.14, indicated in our questionnaire as severe and constant pain. The average one year postoperative VAS score was 3.00, indicated in our questionnaire as mild and intermittent pain. LIMITATIONS: This is a retrospective study and only offers one year follow-up data for patients with instrumented fusions who have undergone endoscopic spine surgery. CONCLUSION: Transforaminal endoscopic discectomy and foraminotomy could be used as a safe, yet, minimally invasive and innovative technique for the treatment of lumbar radiculopathy in the setting of previous instrumented lumbar fusion. IRB approval: Meridian Health: IRB Study # 201206071J

Transforaminal endoscopic discectomy with foraminoplasty for the treatment of spondylolisthesis.

BACKGROUND: Lumbar degenerative spondylolisthesis is a common entity and occurs mainly in elderly patients. The trend in surgery has been to offer decompression with instrumented fusion based on patient-based outcome data and the inherent instability of the condition. OBJECTIVES: Transforaminal endoscopic discectomy and foraminotomy is an ultra-minimally invasive outpatient surgical option available to patients that does not require general anesthesia and does not involve the same amount of destabilizing facet joint removal as a traditional laminectomy and medial facetectomy. The purpose of this study was to assess the benefit of tranforaminal endoscopic discectomy and foraminotomy in patients with lumbar 4-5 (L4-L5) and lumbar 5-sacral 1 (L5-S1) spondylolisthesis and lumbar radiculopathy. METHODS: After Institutional Review Board Approval, charts from 21 consecutive patients with L4-L5 or L5-S1 spondylolisthesis and complaints of lower back and radicular pain who underwent endoscopic procedures between 2007 and 2012 were reviewed. RESULTS: The average pain relief one year postoperatively was reported to be 71.9%, good results as defined by MacNab. The average pre-operative VAS score was 8.48, indicated in our questionnaire as severe and constant pain. The average one year postoperative VAS score was 2.30, indicated in our questionnaire as mild and intermittent pain. LIMITATIONS: This is a retrospective study and only offers one year follow-up data for patients with spondylolisthesis undergoing endoscopic spine surgery for treatment of lumbar radiculopathy. CONCLUSIONS: Endoscopic discectomy is a safe and effective alternative to open back surgery. The one year follow-up data presented here appears to indicate that an ultra-minimally invasive approach to the treatment of lumbar radiculopathy in the setting of spondylolisthesis that has a low complication rate, avoids general anesthesia, and is outpatient might be worth studying in a prospective, longer term way. IRB approval: Meridian Health: IRB Study # 201206071J.

Outpatient, awake, ultra-minimally invasive endoscopic treatment of lumbar disc herniations.

BACKGROUND: Endoscopic discectomy is an ultra- minimally invasive outpatient surgical option for the treatment of lumbar herniated discs. The purpose of this study was to assess the benefit of tranforaminal versus interlaminar endoscopic discectomy in patients with single level Lumbar 5-Sacral 1(L5-S1) disc herniations and lumbar radiculopathy. METHODS: After Institutional Review Board Approval, charts from 41 consecutive patients with complaints of lower back and radicular pain and an L5-S1 herniated disc who underwent an endoscopic procedure between 2007 and 2012 were reviewed. The transforaminal approach was used for patients with far lateral, foraminal, and paracentral disc herniations and the intralaminar approach was used for herniations that were more central. RESULTS: The average pain relief 1-year postoperatively was 75.9% for the transforaminal group and 75.3% for the interlaminar group, both excellent results as defined by MacNab. The average preoperative visual analogue scale (VAS) scores were 8.2 and 8.4 for the transforaminal and interlaminar groups respectively, indicated in our questionnaire as severe and constant pain. The average 1-year postoperative VAS scores were 1.7 and 2.1, indicated in our questionnaire as mild and intermittent pain. There were no complications in the series of patients treated. CONCLUSIONS: The 1-year follow-up data presented here for transforaminal and intralaminar approaches to L5-S1 disc herniations appears to indicate that either approach can be used as determined to best suit the pathology without sacrificing the probability of postoperative pain improvement.

Accelerated partial breast irradiation using 3D conformal radiotherapy: toxicity and cosmetic outcome.

PURPOSE: The aim of this paper is to analyze the incidence of acute and late toxicity and cosmetic outcome in breast cancer patients submitted to breast conserving surgery and three-dimensional conformal radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). METHODS AND MATERIALS: 84 patients were treated with 3D-CRT for APBI. This technique was assessed in patients with low risk stage I breast cancer enrolled from September 2005 to July 2011. The prescribed dose was 34/38.5 Gy delivered in 10 fractions twice daily over 5 consecutive days. Four to five no-coplanar 6 MV beams were used. In all CT scans Gross Tumor Volume (GTV) was defined around the surgical clips. A 1.5 cm margin was added by defining a Clinical Target Volume (CTV). A margin of 1 cm was added to CTV to define the planning target volume (PTV). The dose-volume constraints were followed in accordance with the NSABP/RTOG protocol. Late toxicity was evaluated according to the RTOG grading schema. The cosmetic assessment was performed using the Harvard scale. RESULTS: Median patient age was 66 years (range 51-87). Median follow-up was 36.5 months (range 13-83). The overall incidence of acute skin toxicities was 46.4% for grade 1 and 1% for grade 2. The incidence of late toxicity was 16.7% for grade 1, 2.4% for grade 2 and 3.6% for grade 3. No grade 4 toxicity was observed. The most pronounced grade 2 late toxicity was telangiectasia, developed in three patients. Cosmetics results were excellent for 52%, good for 42%, fair for 5% and poor for 1% of the patients. There was no statistical correlation between toxicity rates and prescribed doses (p = 0.33) or irradiated volume (p = 0.45). CONCLUSIONS: APBI using 3D-CRT is technically feasible with very low acute and late toxicity. Long-term results are needed to assess its efficacy in reducing the incidence of breast relapse.

Clinical success of transforaminal endoscopic discectomy with foraminotomy: a retrospective evaluation.

OBJECTIVE: Transforaminal endoscopic surgery has evolved from an intradiscal procedure to a true foraminal epidural procedure where both a targeted discectomy and foraminal decompression can be performed. The success of transforaminal decompression for radiculopathy using preoperative selective nerve root block as part of a treatment algorithm for single level and multilevel lumbar disc herniations is described here. METHODS: After Institutional Review Board Approval, charts from 195 patients with complaints of lower back and radicular pain who received one or more endoscopic discectomy procedures were reviewed. Visual Analog Scale was applied to each patient preoperatively and 6 months after the procedure. RESULTS: Patients with multi-level pathologies receiving one procedure have an average relief of 69.7% attributed to correct diagnosis of the inflicting level as opposed to 83.9% improvement in patients with a single level herniation. CONCLUSION: Patients with single level lumbar herniations receiving one endoscopic discectomy have excellent outcomes, but with a good response to a selective nerve root block as a preoperative adjunct, patients with multilevel disc herniations also have significant benefit from single level endoscopic discectomy.

A retrospective evaluation of the clinical success of transforaminal endoscopic discectomy with foraminotomy in geriatric patients.

BACKGROUND: The elderly population is growing in the United States. As the oldest old are projected to be the fastest growing part of the elderly population, we must consider how to best treat their degenerative spine conditions when non-operative treatment fails. OBJECTIVES: Transforaminal endoscopic discectomy and foraminotomy is an ultra-minimally invasive outpatient surgical option that does not require general anesthesia and is available to geriatric. The purpose of this study was to assess the benefit of transforaminal endoscopic discectomy and foraminotomy in geriatric patients with single level and multi-level lumbar disc herniations and lumbar radiculopathy. STUDY DESIGN: Retrospective study SETTING: Outpatient surgery center. METHODS: After Institutional Review Board Approval, charts from 50 consecutive patients aged 75 and older with complaints of lower back and radicular pain who underwent one or more endoscopic procedures between 2007 and 2011 were reviewed. RESULTS: The average pain relief 6 months postoperatively was reported to be 71.8%, good results as defined by MacNab. The average pre-operative VAS score was 9.04, indicated in our questionnaire as severe and constant pain. The average 6 month post-operative VAS score was 2.63, indicated in our questionnaire as mild and intermittent pain. LIMITATIONS: This is a retrospective study and only offers 6 month follow-up data for geriatric patients undergoing endoscopic spine surgery. CONCLUSIONS: Endoscopic discectomy is a safe and effective alternative to open back surgery. The 6-month follow-up data presented here appears to indicate that an ultra-minimally invasive approach to the geriatric spine that has a low complication rate, avoids general anesthesia, and is outpatient might be worth studying in a prospective, longer term way. IRB approval: Meridian Health: IRB Study # 201206071J.

Endoscopic transforaminal discectomy for an extruded lumbar disc herniation.

Microsurgery for lumbar herniated discs that require surgical intervention is a very successful and well-described technique, whether performed through more traditional "open" microsurgical retractors or through minimally-invasive "tube" retractors. Surgery for extruded lumbar disc fragments that migrate caudad or cephalad from the disc origin may typically require modifying the standard hemilaminotomy by removing additional laminar bone to retrieve the migrated fragment. Although midline and paramedian Wiltse approaches have been the standard methods for resecting herniated lumbar disc fragments, advances in neuroendoscopic techniques have expanded the potential targets for transforaminal endoscopic treatment to include extruded lumbar disc fragments. Sequestrations migrated cephalad or caudal to the disc can be removed using specialized flexible instruments. The instruments enable the surgeon to circumnavigate and reach into the epidural space and as far as the mid-vertebral body. The authors present a case of an endoscopically resected lumbar herniated disc fragment extruded caudad behind the inferior vertebral body through a transforaminal approach in an awake patient using local anesthetic. Radiographic and endoscopic visualization make it possible to access intracanal pathology. Although more traditional lumbar disc surgery is widely performed and is safe and effective, neuroendoscopic procedures may also allow a safe and effective approach for even extruded disc fragments for patients who cannot tolerate general anesthesia or are seeking the most minimally invasive option. Endoscopic discectomy is a minimally invasive alternative to open back surgery. Maintained spinal stability and absence or minimal formation of scar tissue allow for ease of subsequent surgeries, both open and minimally invasive (if needed).

Pretreatment patient-specific IMRT quality assurance: a correlation study between gamma index and patient clinical dose volume histogram.

PURPOSE: The aim of this work is to investigate the predictive power of a common conventional intensity modulated radiation therapy (IMRT) quality assurance (QA) performance metric, the gamma passing rate (%GP), through the analysis of the sensitivity and of the correlation between %GP and different dose discrepancies between planned dose-volume histogram (DVH) and perturbed DVH. The perturbed DVH is calculated by using a dedicated software, 3DVH (Sun Nuclear Corporation, Melbourne, FL), which is able to modify the dose distribution calculated by the treatment planning system (TPS) according to the dose discrepancies detected with planar measurements in order to predict the delivered 3D dose distribution in the patient. METHODS: Twenty-seven high-risk prostate cancer (PP) patients and 15 head and neck (HN) cancer patients, treated with IMRT technique, were analyzed. Pretreatment verifications were performed for all patients' plans by acquiring planar dose distributions of each treatment field with 2D-diode array. Measured dose distributions were compared to the calculated ones using the gamma index (GI) method applying both global (Van Dyk) and local normalization, and %GP were generated for each pair of planar doses using the following acceptance criteria: 1%∕1, 2%∕2, and 3%∕3 mm. Planar dose distributions acquired during pretreatment verifications, together with patient's DICOM RT plan, RT structure set, and RT dose files from TPS were loaded into the 3DVH software. Percentage dose differences (%DE) between DVHs, obtained by TPS and by 3DVH, were calculated; statistical correlation between %DE and %GP was studied by using Pearson's correlation coefficient (r). This analysis was performed, for each patient, on planning target volumes and on some typical organs at risk of the prostatic and head and neck anatomical district. The sensitivity was calculated to correctly identify the pretreatment plans with high dose errors and to quantify the incidence of false negatives, on varying the gamma index method. RESULTS: Analysis of %DE vs %GP showed that there were only weak correlations (Pearson's r-values < 0.8). The results also showed numerous instances of false negatives (cases where high IMRT QA passing rates did not imply good agreement in anatomy dose metrics) and the reverse, mainly for the 3%∕3 mm global gamma passing rate. CONCLUSIONS: The lack of correlation between conventional IMRT QA performance metrics gamma passing rates and dose errors in DVHs values and the low sensitivity of 3%∕3 mm global gamma method show that the most common published acceptance criteria have disputable predictive power for per-patient IMRT QA.