Perioperative Pain Management for Shoulder Surgery‌‌

 

Summary

Adequate management of pain after shoulder surgery is paramount to post-operative recovery. Regional anesthesia has proven to provide superior pain control and recovery. Several brachial plexus blocks have been described with intrascalene being the most common employed. A full knowledge of anatomy as well as the indications and potential complications associated with regional anesthesia is required by the physician.

Keywords: Pain management, peripheral nerve blocks, intrascalene, supraclavicular

 

1. General overview

   1. First peripheral block was performed by William Halsted with cocaine in 1885

   2. Over the past 30 years there has been an increasing trend in the use of peripheral nerve blocks for postoperative pain management

   3. Adequate pain control via peripheral block:

      1. Decreases hospital length of stay

      2. Allows transition from traditional inpatient surgery to outpatient

      3. Decrease opioid use and associated opioid side effects

      4. Enhances participation in rehabilitation

      5. Improve functions and patient satisfaction outcomes

      6. Enhance cost-effectiveness.

   4. Vital to understand the indications and potential complications associated with regional anesthesia.

       

2. Anatomy

   1. Brachial plexus (▶Fig. 22.1):

      1. Five roots: C5, C6, C7, C8, and T1

         1. Level of intrascalene block.

      2. Three trunks: Upper, middle, and lower

         1. Level of supraclavicular block.

      3. Six divisions: Anterior and posterior divisions of three trunks

      4. Three cords: Posterior, lateral, and medial

         1. Level of intraclavicular block.

      5. Five branches: Median, axillary, radial, musculocutaneous, and ulnar nerves

         1. Level of axillary block.

             

             

             

             

             

            Fig. 22.1 Brachial plexus anatomy. Areas within borders represent anatomic locations of common regional blocks for upper extremity surgery. From proximal to distal: interscalene, supraclavicular, infraclavicular, and axillary.

             

   2. Shoulder sensory innervation:

      1. Superior region:

         1. Superficial cervical plexus (C3–C4):

            1. Supraclavicular nerve.

      2. Axillary region:

         1. T2 nerve root.

      3. Shoulder capsule, subacromial bursa, acromioclavicular joint, cutaneous tissue:

         1. Suprascapular nerve—primarily C5, C6 with some C4.

   3. Four anatomic regions pertinent to peripheral nerve blocks (▶Fig. 22.2):

      1. Intrascalene:

         1. Potential space between anterior and middle scalenes

         2. Targets brachial plexus at root-trunk level

         3. Most commonly preformed

         4. Effective for shoulder, proximal humerus, and distal clavicle

         5. Ulnar sparing:

            1. C8 frequently not covered

            2. Additional block required for surgery around the elbow.

                

                

                

                

               Fig. 22.2 Anterior and posterior distribution of common regional blocks. (a) Interscalene.

               (b) Supraclavicular. (c) Infraclavicular. (d) Axillary.

                

      2. Supraclavicular:

         1. Superior to clavicle at the level of plexus trunks

         2. Between anterior and middle scalenes at the first rib

         3. Apical lung vulnerable

         4. Suitable for shoulder; theoretically does not cover superior aspect of shoulder, arm, and elbow: forearm hand adequately covered.

      3. Infraclavicular:

         1. Boarders consist of:

            1. Superior—posterior aspect of clavicle

            2. Inferior—soft tissues of axilla

            3. Anterior—pectoralis minor

            4. Posterior subscapularis.

                

         2. Level of the cords before axillary and musculocutaneous nerves exit

         3. Shoulder not covered; arm, elbow, and forearm hand adequately covered.

      4. Axillary and suprascapular:

         1. In combination similar shoulder coverage compared with intrascalene block

         2. Axillary:

            1. Located beneath glenohumeral joint between the chest wall and medial upper arm

            2. In isolation may be adequate for elbow surgery.

         3. Suprascapular:

            1. Level of the suprascapular notch.

                

3. Regional anesthesia

   1. Definition:

      1. Administration of local anesthetics to an area resulting in motor and sensory blockade

      2. Central versus peripheral blocks depend on distance from spinal cord.

   2. Peripheral nerve block should be conducted in awake patients:

      1. Allow for real-time feedback from patient and avoidance of complications

      2. Supported by level 1 evidence.

   3. Localization techniques:

      1. Ultrasound:

         1. Faster block onset and improved success versus peripheral nerve stimulator

         2. Less risk of vascular puncture.

      2. Peripheral nerve stimulator:

         1. Low intensity, short-duration electrical stimulus

         2. Obtain a response (twitch or sensation) to localize peripheral nerve.

      3. Needle guidance:

         1. First methods based on anatomical landmarks and elicitation of paresthesias as the needle was advanced through the sheath.

   4. Single injection versus continuous catheter:

      1. Single injection:

         1. Duration varies from 2 to 48 hours, average 12 hours.

      2. Continuous catheter:

         1. Continuous anesthesia providing relief beyond 12 hours

         2. Patients discharged home with “pump”

             

         3. Studies demonstrated decreased opioid use, improved pain scores, and improved sleep patterns with use‌

         4. Technically more difficult

         5. Concern for toxic volume of anesthetic.

             

4. Patient factors to consider

   1. Obesity:

      1. Patients with body mass index (BMI) >30 are 1.62 times more likely to have a failed block.

   2. Use of systemic anticoagulation:

      1. American Society of Regional Anesthesia and Pain Medicine consensus statement—patients who are mildly anticoagulated are safe to undergo block

      2. International normalized ratio (INR) <3 noted to have 3 months bleeding risk of 3%. Increased to 7% with INR over 4.

   3. Pulmonary disease:

      1. Relative contraindication to proximal blocks

      2. Concern in patients with poor respiratory reserve due to long-term phrenic nerve injury caused by intraneural injection, trauma, or toxicity

      3. Using ultrasound and low volume have been recently shown to be safe:

         1. A randomized clinical trial that compared ultrasound-guided injections of ropivacaine, 20 mL and 5 mL, found that patients who received the low volume injection had significantly less respiratory compromise without a significant difference in pain score, opioid consumption, or sleep quality 24 hours after surgery.

      4. Consider axillary and supraclavicular block versus intrascalene or supraclavicular to avoid risk of injury to apical lung or phrenic nerve compromise.

          

5. Medications

   1. Block agents:

      1. Administration:

         1. Dose dependent on agent used, technique, and preference of physician.

      2. Long-acting agents:

         1. Bupivacaine:

            1. Local anesthetic

            2. Associated with life-threatening cardiotoxicity and neurotoxicity

               secondary to stereospecificity to receptors.

         2. Levobupivacaine and ropivacaine:

            1. Optically pure isomer

            2. Less neurotoxicity and cardiotoxicity compared with bupivacaine

            3. No significant difference in efficacy.

                

   2. Adjuvants:

      1. Epinephrine:

         1. Decreases systemic absorption

         2. Potential increased uptake by nerve

         3. Possible risk of bradycardic and hypotensive episodes

         4. Potential for allergy.

      2. Clonidine:

         1. Alpha 2 adrenergic agonist

         2. Improves effectiveness of local anesthetic

         3. Independently acts as analgesic

         4. Potential for rebound hypotension.

      3. Dexamethasone:

         1. Increases duration of sensory blockade

         2. Mechanism not well understood

         3. Has been shown in randomized trial of shoulder surgery to increase duration of sensory block and decrease opioid use.

             

6. Complications

   1. Systemic:

      1. Major:

         1. Cardiac arrest

         2. Respiratory failure

         3. Seizures

         4. Death.

      2. Minor:

         1. Agitation, anxiety

         2. Visual disturbances

         3. Perioral anesthesia

         4. Dizziness

         5. Muscle fibrillation

         6. Tinnitus.

      3. Incidence reported to be less than 1 in 1,000

      4. No reported cases of death attributed to peripheral block with ropivacaine or levobupivacaine

      5. Possible role for intralipid infusion to manage cardiac toxicity

          

      6. Patients in beach chair position may be more prone to bradycardia and hypotension:

         1. Mediated by Bezold-Jarisch reflex:

            1. Venous pooling caused by seated position increases sympathetic tone resulting in a low-volume hypercontractile ventricle

            2. May be aggravated by epinephrine.

   2. Nerve injury:

      1. Relatively rare, approximately 0.4 per 1,000 blocks

      2. Paresthesias during block placement have a higher association with postoperative neurological symptoms.

   3. Pneumothorax:

      1. Most common with supraclavicular block

      2. Decreased risk with use of ultrasound guidance.

 

Suggested Readings

Bruce BG, Green A, Blaine TA, Wesner LV. Brachial plexus blocks for upper extremity orthopaedic surgery. J Am

Acad Orthop Surg 2012;20(1):38–47

Hughes MS, Matava MJ, Wright RW, Brophy RH, Smith MV. Interscalene brachial plexus block for arthroscopic

shoulder surgery: a systematic review. J Bone Joint Surg Am 2013;95(14):1318–1324

Hussain N, Goldar G, Ragina N, Banfield L, Laffey JG, Abdallah FW. Suprascapular and interscalene nerve block

for shoulder surgery: a systematic review and meta-analysis. Anesthesiology 2017;127(6):998–1013

Mian A, Chaudhry I, Huang R, Rizk E, Tubbs RS, Loukas M. Brachial plexus anesthesia: a review of the relevant

anatomy, complications, and anatomical variations. Clin Anat 2014;27(2):210–221 Review

Review Srikumaran U, Stein BE, Tan EW, Freehill MT, Wilckens JH. Upper