UW Shoulder and Elbow Academy: Interscalene blocks for shoulder surgery

Single Shot Interscalene Regional Anesthesia Provides Noninferior Analgesia And Decreased Complications Compared With An Indwelling Catheter for Arthroscopic And Reconstructive Shoulder Surgery

These authors compared the efficacy, safety, and complication rates of regional anesthesia in shoulder surgery in 1888 patients lumping together those who underwent shoulder arthroplasty (n=417) and arthroscopic shoulder surgery (n=1471). The blocks were performed under ultrasound guidance by an anesthesiologist with subspecialty training in regional anesthesia.

Ten times as many patients had a continuous interscalene nerve block with a catheter (CIB n=1728) than a single shot interscalene block (SSIB n=160). The allocation was not randomized, but based on patient risk factors and surgeon preference. Patients received phone calls on postoperative days one, two, and seven and fourteen to assess pain levels (NRS) and complications.

They arbitrarily dismissed block related symptoms lasting a week or less as "side effects"; symptoms lasting beyond a week were labeled “complications”.

Using this definition, there were 3 complications (2%) in the SSIB group and 172 complications (10%) in the CIB group. The most frequent complication in the CIB group was shortness of breath (n=135) while in the SSIB group was persistent numbness (n=2).

Ten patients in the CIB group required Emergency Department (ED) visits secondary to block complications compared to no ED visits in the SSIB group. The relative risk for having a documented complication was 5 times greater in the CIB group. Ten patients in the CIB cohort had block-related ED visits; whereas, no patients in the SSIB had an ED visit.

CIB was associated with $848.18 more hospital and provider payments relative to SSIB. In addition to the direct costs, patients receiving CIB require the added burden of an additional staff member or established members of the clinical team to call and check on patients with indwelling catheters. Even more costly was is the diagnostic testing for pulmonay complications in the ED, which often includes both cardiac and pulmonary embolism evaluation.

Comment: This study again demonstrates the cost and complications lasting over 1 week associated with interscalene blocks. They did not analyze the complications lasting less than 1 week - many of which may have been substantial.

A randomized controlled trial, Single-Shot Versus Continuous Interscalene Block for Postoperative Pain Control After Shoulder Arthroplasty: A Prospective Randomized Clinical Trial, found a 21% complication rate for continuous block and a 5.4% rate of complications for single shot blocks.

In Continuous versus single shot brachial plexus block and their relationship to discharge barriers and length of stay, the authors conducted a retrospective review of 697 patients undergoing upper extremity arthroplasty comparing the rate of complications and incidence of potential barriers to discharge and length of stay of patients receiving continuous vs. single-shot perineural brachial plexus block.

The complication rate was 12% (n=63) for the indwelling group and 17% (n=30) for the single-shot group.

The findings of a recent review, Pain Management After Shoulder Arthroplasty: A Systematic Review of Randomized Controlled Trials, are important.Those authors found that the overall cost of single-injection block and continuous block can approach $1,500 and $1,850, respectively, if professional fees are included.

Complications seem with interscalene blocks include phrenic nerve palsy, dyspnea, and persistent distal neuropathy; complications after interscale blocks have been reported in up to 36% of cases. Rebound pain can be substantial when the block wears off 8-24 hours after surgery. In some cases, rebound pain can lead to greater pain levels and increased narcotic requirement after interscalene block compared to local infiltration. While higher concentrations of an anesthetic such as ropivacaine may produce a more dense block, undesirable effects such as a more pronounced rebound effect, a prolonged motor blockade, and risk of neurotoxicity

Complications of continuous interscalene block are more frequent than for single shot blocks, including phrenic nerve block, hemidiaphragmatic palsy, dyspnea, dysphagia, infection, dislodgement, and catheter malposition.

In our practice blocks are avoided for almost all arthroplasties. Pain management starts preoperatively with preoperative education, Tylenol, Celebrex and Gabapentin. Patients are started on oral analgesics in the recovery room.

With this "block-less" program our patients have minimal difficulty in starting their immediate postoperative range of motion exercises as is shown here for a 63 year old man on the morning after his total shoulder arthroplasty immediately prior to his discharge.

Our reasons for avoiding routine interscalene blocks for shoulder arthroplasty include (1) desire for documentation of neurological status immediately after surgery, (2) wanting to avoid having a flail unprotected arm as we start immediate postoperative motion exercises, (3) eliminating the risk of block-related neurologic or pulmonary complications, (4) avoiding phrenic nerve paresis with the attendant respiratory compromise, (5) eliminating the inconvenience of a failed block, (6) reducing the cost (professional and materials) associated with two different anesthetics (block + general), (7) avoiding the problem of acute rebound pain in the middle of the first postoperative night, and (8) the reluctance of some patients to have a needle placed in their neck.