A Prospective Randomized Trial of Prognostic Genicular Nerve Blocks to Determine the Predictive Value for the Outcome of Cooled Radiofrequency Ablation for Chronic Knee Pain Due to Osteoarthritis.

Background and Objectives: Genicular nerve radiofrequency ablation is an effective treatment for patients with chronic pain due to knee osteoarthritis; however, little is known about factors that predict procedure success. The current study evaluated the utility of genicular nerve blocks to predict the outcome of genicular nerve cooled radiofrequency ablation (cRFA) in patients with osteoarthritis. Methods: This randomized comparative trial included patients with chronic knee pain due to osteoarthritis. Participants were randomized to receive a genicular nerve block or no block prior to cRFA. Patients receiving a prognostic block that demonstrated ≥50% pain relief for six hours received cRFA. The primary outcome was the proportion of participants with ≥50% reduction in knee pain at six months. Results: Twenty-nine participants (36 knees) had cRFA following a prognostic block, and 25 patients (35 knees) had cRFA without a block. Seventeen participants (58.6%) in the prognostic block group and 16 (64.0%) in the no block group had ≥50% pain relief at six months (P = 0.34). A 15-point decrease in the Western Ontario and McMaster Universities Osteoarthritis Index at six months was present in 17 of 29 (55.2%) in the prognostic block group and 15 of 25 (60%) in the no block group (P = 0.36). Conclusions: This study demonstrated clinically meaningful improvements in pain and physical function up to six months following cRFA. A prognostic genicular nerve block using a local anesthetic volume of 1 mL at each injection site and a threshold of ≥ 50% pain relief for subsequent cRFA eligibility did not improve the rate of treatment success.

The Impact of Body Mass Index on Fluoroscopy Time During Lumbar Epidural Steroid Injection; A Multicenter Cohort Study.

Objective: This study aimed to assess the relationship between BMI and fluoroscopy time during lumbar epidural steroid injections (LESIs) performed for lumbosacral radicular pain. Design: Multicenter retrospective cohort study. Setting: Three academic, outpatient pain treatment centers. Subjects: Patients who underwent fluoroscopically guided LESI. Methods: Mean and standard deviation (SD) fluoroscopy time were compared between patients with normal (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30.0 kg/m2) BMI. Statistical significance was set at P=0.01 due to multiple comparisons. Results: A total of 2,930 procedure encounters were included, consisting of 598 interlaminar LESIs and 2,332 transforaminal LESIs. Fluoroscopy time was significantly longer in the obese patients compared to normal and overweight patients during interlaminar LESI (P < 0.01). Fluoroscopy time was significantly longer with each increasing BMI category in during transforaminal LESI (P < 0.01). These relationships remained when a trainee was involved (P < 0.01; P<0.01), during repeat injections (P < 0.01; P < 0.01), and during bilateral transforaminal LESIs (P < 0.01). While longer fluoroscopy times were required in high BMI categories during L5-S1 transforaminal LESI (P < 0.01), there was no relationship between fluoroscopy time and BMI during L4-L5 and S1 transforaminal LESI (P = 0.02; P = 0.13). Fluoroscopy time during interlaminar LESI compared to transforaminal LESI was significantly lower within all BMI categories (all P<0.01). Conclusions: The findings of this study indicate that fluoroscopy time is increased during interlaminar LESIs and during L5-S1 transforaminal LESIs in patients who are obese. These relationships are not affected by injection number, performance of bilateral injections, or trainee involvement. Further study is needed to determine if this increase in fluoroscopy time is indicative of a clinically significant associated increase in radiation dose.

Accuracy of colonoscopic localization.

BACKGROUND: The objective of this study was to evaluate the accuracy of preoperative colonoscopic localization of colonic lesions. Localization of the colonic lesion plays a key role in determining the type of operation a patient may require. Inaccurate localization may result in removal of the wrong segment of colon and/or a change in the operation performed. METHODS: A retrospective review of patients who had a colon resection by a single surgeon after preoperative colonoscopic localization between 1991 and 2008 was performed. A comparison of the preoperative colonoscopic localization and the final intraoperative localization was made. Clinical and demographic information was gathered to determine accuracy rates and identify predictive factors. RESULTS: Three hundred and seventy-four patients were included and 184 (49%) were male. The mean age was 61.6 years. Three hundred and sixty-two (97%) patients underwent colon resection for cancer. Fifteen (4%) patients had nonconcordant colonoscopic and intraoperative findings. Fourteen of the 15 (93%) were resected for cancer and 1 for inflammatory bowel disease (IBD). Seven (47%) lesions were inaccurately localized in the sigmoid colon, four (27%) in the descending colon, two (13%) in the ascending colon, one (7%) in the rectum, and one (7%) lesion was not visualized preoperatively. Eleven of the 15 (73%) patients with nonconcordant localization had a modification of their planned procedure. Ten patients underwent a different segmental colectomy and one patient had an extended resection. CONCLUSION: Preoperative colonoscopic localization of colorectal lesions was reasonably accurate (96%) in this large series. The majority of inaccurately identified lesions occurred in the sigmoid and descending colon. Erroneous localization, even though not common, can result in significant changes in the intraoperative plan and the ultimate outcome. Therefore, every effort should be made to localize the lesion before surgery, especially when thought to be in the left or sigmoid colon, to reduce the need for intraoperative localization efforts, the need for an intraoperative change in procedure, and the risk of a surprise for the patient after surgery.