Chapter 121 - Neurogenic TOS Flashcards
Trunks of the brachial plexus and its contributors
Upper trunk: C5, C6 Middle trunk C7 Lower trunk C8, T1
Function of the long thoracic nerve
Serratus anterior muscle
Most common muscular variation of the TO
Scalene minimus muscle
Classification of congenital bands and ligaments within the scalene triangle
TABLE 121.1
Normal composition of anterior scalene with Type I or II fibers and changes in nTOS
Type I slow twitch Type II fast twitch normally equal in nTOS Type I increase to 78%
Epidemiology nTOS
Age 20-40 70% women no inherited patterns or medical conditions
Symptoms of nTOS
1) pain 2) dysesthesia 3) numbness 4) weakness 5) headache (spasm of trapezius and paraspinous) not distinguishable to a single peripheral nerve distribution
Ulnar never compression at elbow causes
Cubital compression syndrome
Median nerve compression at wrist causes
Carpal tunnel syndrome
Pain over shoulder joint suggest
Rotator cuff pathology
Tenderness over trapezius muscle suggest
Fibromyalgia
Botulinum toxin injection to scalene muscle
1) effect 2-3 months 2) repeated use not possible due to immune response 3) side effects (dysphagia) not generally recommended
Differential diagnosis of nTOS lists of conditions
TABLE 121.2
diagnostic criteria of nTOS by the Consortium for Research and Education of TOS
TABLE 121.3
Conservative management of nTOS
Physiotherapy 4-8 weeks
Focus of physiotherapy in nTOS
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
Benefit of transaxillary approach for nTOS treatment
1) cosmetic scar 2) reliable exposure for first rib 3) allow partial resection of anterior scalene and ligament/bands
Disadvantage of transaxillary approach for TOS
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
Transaxillary TOS steps
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
nerve injured and post-op complication in excessive elevation of the arm in transaxillary exposure
Second intercostobrachial cutaneous nerve postop pain and numbness along medial aspect of upper arm
Advantage to supraclavicular approach to TOS
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
Supraclavicular approach to TOS steps
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
Pec minor tenotomy steps
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
Rate of phrenic nerve injury in TOS treatment
10% retraction and temporary only usually asymptomatic recover in 10 months
Outcomes of nTOS surgery classes
1) Excellent = complete relief 2) good = partial relief 3) fair = partial relieve with persistent symptoms 4) poor no improvement
Anterior scalenectomy/scalenotomy % of good response
56-58%
Transaxillary first rib resection nTOS results percentage good
80%
Supraclavicular first rib and anterior and middle scalenectomy results percentage good
77%
Outcome differences between approaches
None significant
Predictors of poor outcome
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
Key points from Sanders et al
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
Key points in reoperating on persistent nTOS
1) resect more first rib and cervical rib 2) more anterior scalene 3) neurolysis of brachial plexus 4) pec minor tenotomy
