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Updated: Jul 7, 2026

Clinical Efficacy of Small Needle Knife Therapy on Stage I-II Frozen Shoulder
Published on: November 17, 2023
Successful continuous interscalene analgesia for ambulatory shoulder surgery in a private practice setting
Michael J Fredrickson1, Craig M Ball, Adam J Dalgleish
1Department of Anesthesiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand. fredrickson@actrix.co.nz
Background And Objectives:
Large prospective studies evaluating continuous interscalene block for shoulder surgery have thus far been limited to inpatient and university teaching practices. Shoulder surgery is increasingly being performed on an outpatient basis. The aim of this case series was to prospectively evaluate a large series of interscalene catheters for ambulatory shoulder surgery in a private practice setting.
Methods:
A single operator placed nonstimulating catheters using a combination of ultrasound and nerve stimulation. Following postanesthesia care unit (PACU) discharge, opioid-like analgesic adjuvants other than tramadol were avoided unless patients experienced inadequate pain relief. All patients were assessed in the PACU, on the first postoperative morning, and at 3 weeks for catheter effectiveness and for acute and chronic complications. Pain scores and patient satisfaction were assessed in subgroups of 100 consecutive patients.
Results:
Three hundred patients were studied. The first attempt catheter success rate was 96%. In all but 1 patient, ineffective catheters in the PACU were effectively reinserted. Thirteen patients experienced inadequate pain relief after leaving the PACU. Of these patients, 5 were rescued with additional ropivacaine, 3 had the catheter effectively reinserted, and 5 were managed with oral opioids. One patient required antibiotic treatment for catheter site infection. Neurological sequelae potentially attributable to the catheter were present in 3 patients at 3 weeks, and remained in 1 patient at 4 weeks. This patient's symptoms resolved at 6 months.
Conclusions:
Continuous interscalene block for ambulatory shoulder surgery in a private practice setting had a high success rate, a low complication rate, and enabled the avoidance of the use of potent opioids in 98% of patients.
