Chapter 121 - Neurogenic TOS

Question 1

Trunks of the brachial plexus and its contributors

Answer 1

Upper trunk: C5, C6 Middle trunk C7 Lower trunk C8, T1

Question 2

Function of the long thoracic nerve

Answer 2

Serratus anterior muscle

Question 3

Most common muscular variation of the TO

Answer 3

Scalene minimus muscle

Question 4

Classification of congenital bands and ligaments within the scalene triangle

Answer 4

TABLE 121.1

Question 5

Normal composition of anterior scalene with Type I or II fibers and changes in nTOS

Answer 5

Type I slow twitch Type II fast twitch normally equal in nTOS Type I increase to 78%

Question 6

Epidemiology nTOS

Answer 6

Age 20-40 70% women no inherited patterns or medical conditions

Question 7

Symptoms of nTOS

Answer 7

1) pain 2) dysesthesia 3) numbness 4) weakness 5) headache (spasm of trapezius and paraspinous) not distinguishable to a single peripheral nerve distribution

Question 8

Ulnar never compression at elbow causes

Answer 8

Cubital compression syndrome

Question 9

Median nerve compression at wrist causes

Answer 9

Carpal tunnel syndrome

Question 10

Pain over shoulder joint suggest

Answer 10

Rotator cuff pathology

Question 11

Tenderness over trapezius muscle suggest

Answer 11

Fibromyalgia

Question 12

Botulinum toxin injection to scalene muscle

Answer 12

1) effect 2-3 months 2) repeated use not possible due to immune response 3) side effects (dysphagia) not generally recommended

Question 13

Differential diagnosis of nTOS lists of conditions

Answer 13

TABLE 121.2

Question 14

diagnostic criteria of nTOS by the Consortium for Research and Education of TOS

Answer 14

TABLE 121.3

Question 15

Conservative management of nTOS

Answer 15

Physiotherapy 4-8 weeks

Question 16

Focus of physiotherapy in nTOS

Answer 16

1) slope of shoulder girdle 2) angle of clavicle 3) position of scapula on thorax 4) position of humerus on glenoid 5) posturing of head and neck 6) alignment of cervical and upper thoracic spine

Question 17

Benefit of transaxillary approach for nTOS treatment

Answer 17

1) cosmetic scar 2) reliable exposure for first rib 3) allow partial resection of anterior scalene and ligament/bands

Question 18

Disadvantage of transaxillary approach for TOS

Answer 18

1) incomplete exposure of structures of scalene triangle 2) cannot perform anterior and middle scalenectomy or brachial plexus neurolysis 3) necessity for 1st rib resection in all cases 4) cannot reconstruct vessel

Question 19

Transaxillary TOS steps

Answer 19

1) back of table raised 30 degree 2) ipsilateral shoulder raised 3) prep arm circumferentially 4) transverse incision lower border of axillary hairline 5) extend from anterior border of lattismus dorsi to lateral edge of pec major 6) long thoracic, thoracodorsal, second intercostobrachial nerve identified near chest wall 7) palpate first rib at the upper reaches of the areolar tissue plane along chest wall 8) Deaver retractor to lift subcutaneous tissue and axillary contets from chest wall 9) Subclavian vein and artery identified along with anterior scalene 10) dissect anterior scalene a few cm from rib 11) divide muscle at highest level possible with scissors 12) divide soft tissue attachment to first rib 13) divide subclavius muscle tendon and the costosternal/costoclavicular ligaments 14) periosteal elevator along inferior border of rib and divide intercostal muscles 15) push parietal pleura away from rib 16) middle scalene detached from rib avoiding long thoracic nerve laterally by pushing it away 17) bone cutter to cut out rib 18) rongeur to trim remains of bone to smooth surfaces 19) extrapleural dissection can be done to perform sympathectomy if CRPS exist 20) release soft tissue and bands around plexus 21) test for airleak with PEEP and fluid

Question 20

nerve injured and post-op complication in excessive elevation of the arm in transaxillary exposure

Answer 20

Second intercostobrachial cutaneous nerve postop pain and numbness along medial aspect of upper arm

Question 21

Advantage to supraclavicular approach to TOS

Answer 21

1) complete resection of scalene muscles 2) plexus neurolysis 3) visualization of all 5 nerve roots 4) allow vascular reconstruction 5) removal of anteromedial first rib requires second infraclavicular incision

Question 22

Supraclavicular approach to TOS steps

Answer 22

1) supine with head elevated 30 degrees 2) hips and knees flexed and neck extended turned to opposite side 3) arm prepped and held over abdomen to allow intraoperative motion assessment 4) transverse skin incision 2 fingers above clavicle from lateral border of SCM 5) through plastysma to scalene fat pad 6) mobilize scalene fat pad starting at lateral border of IJ and reflect laterally 7) phrenic nerve identified on anterior scalene from lateral to medial direction 8) anterior scalene dissected and divided 9) remove scalene minimus fibers 10) identify nerve roots and remove inflammatory scar tissue 11) divide attachment of middle scalene extending posteriorly 12) care taken not to divide long thoracic nerve (may be multiple branches) 13) examine possible contribution of first rib in compression to decide on removal 14) push pleural membrane away with gauze 15) cut rib and rongeur fragments

Question 23

Pec minor tenotomy steps

Answer 23

1) short verticle incision lateral infraclavicular space 2) adjacent to deltopectoral groove 3) lateral edge of pec major retracted medially 4) encircle pec minor tendon and divide immediately inferior to insertion on coracoid process

Question 24

Rate of phrenic nerve injury in TOS treatment

Answer 24

10% retraction and temporary only usually asymptomatic recover in 10 months

Question 25

Outcomes of nTOS surgery classes

Answer 25

1) Excellent = complete relief 2) good = partial relief 3) fair = partial relieve with persistent symptoms 4) poor no improvement

Question 26

Anterior scalenectomy/scalenotomy % of good response

Answer 26

56-58%

Question 27

Transaxillary first rib resection nTOS results percentage good

Answer 27

80%

Question 28

Supraclavicular first rib and anterior and middle scalenectomy results percentage good

Answer 28

77%

Question 29

Outcome differences between approaches

Answer 29

None significant

Question 30

Predictors of poor outcome

Answer 30

1) amount of disability before surgery 2) longer interval between injury and nTOS diagnosis 3) age at time of surgery 4) coexsisting conditions 5) chronic pain syndromes 6) depression 7) lack of response to anterior scalene block 8) diffuse upper extremity symptoms

Question 31

Key points from Sanders et al

Answer 31

1) cervical rib or anomalous first rib in nTOS does not improve success of surgery 2) neck trauma most common cause of nTOS 3) cervical/anomalous first rib are predisposing factors but not causes 4) surgery for nTOS in cervical ribs should include both cervical and first rib resection

Question 32

Key points in reoperating on persistent nTOS

Answer 32

1) resect more first rib and cervical rib 2) more anterior scalene 3) neurolysis of brachial plexus 4) pec minor tenotomy