summary Obstetric Brachial Plexopathy is injury to the brachial plexus that occurs during birth usually as a result of a stretching injury from a difficult vaginal delivery. Diagnosis is made clinically and depends on the nerve roots involved. Treatment can be observation or operative depending on the nerve roots involved, the severity of injury, and the location of the nerve injury. Epidemiology Incidence approximately 1 to 4 per 1,000 live births decreasing in frequency due to improved obstetric care Anatomic location often right sided or bilateral Risk factors large for gestational age (macrosomia) multiparous pregnancy difficult presentation shoulder dystocia forceps delivery breech position prolonged labor Etiology Cause usually a stretching injury from a difficult vaginal delivery some rare cases reported following C-sections Associated orthopedic conditions glenohumeral dysplasia increased glenoid retroversion, humeral head flattening, posterior humeral head subluxation develops in 70% of infants with obstetric brachial plexopathy caused by Internal rotation contracture (loss of external rotation) elbow flexion contracture etiology is unclear, likely due to persistent relative triceps weakness (C7) compared with biceps (C5-6) clavicle and humerus fractures torticollis Anatomy Brachial plexus diagram Narakas Classification Group Characteristics Roots Group I (Duchenne-Erb's Palsy) Paralysis of deltoid and biceps. Intact wrist and digital flexion/extension. C5-C6 Group II (Intermediate Paralysis) Paralysis of deltoid, biceps, and wrist and digital extension. Intact wrist and digital flexion. C5-C7 Group III (Total Brachial Plexus Palsy) Flail extremity without Horner's syndrome C5-T1 Group IV (Total Brachial Plexus Palsy with Horner's syndrome) Flail extremity with Horner's syndrome C5-T1 Waters Classification of Glenohumeral Deformity Waters Classification of Glenohumeral Deformity Classification Radiographic features Type I < 5 degree difference in retroversion Type II > 5 degree difference in retroversion Type III Posterior humeral head subluxation < 35% anterior to scapular spine axis Type IV Presence of false glenoid Type V Flattening of humeral head, progressive/ complete humeral head dislocation Type VI Infantile posterior dislocation Type VII Proximal humeral growth arrest Presentation General Symptoms lack of active hand and arm motion Physical exam upper extremity exam arm hangs limp at side in an adducted and internally rotated position decreased shoulder external rotation affected shoulder subluxates posteriorly provocative testing stimulate neonatal reflexes including Moro, asymmetric tonic neck and Vojta reflexes pain with gentle shaking of a flail arm may indicate pseudoparalysis from infection or fracture rather than nerve palsy Hospital for Sick Children Active Movement Scale (AMS) muscle strength grading system full range of motion with gravity eliminated (score of 4) must be achieved before higher scores may be assigned Imaging Radiographs may be useful for evaluation of clavicle or humerus fractures limited utility in infant given minimal ossification of humeral head and glenoid axillary view to evaluate position of humeral head if patient is older and suspicion is high for joint subluxation Myelography/CT myelography/MRI may be used to distinguish between root avulsion and extraforaminal rupture EMG/NCV poor reliability and often underestimate the severity of injury Ultrasound allows for assessment of joint subluxation or dislocation Erb's Palsy (C5,6) - Upper Lesion Most common type Mechanism results from lateral flexion of the head towards the contralateral shoulder with depression of the ipsilateral shoulder producing traction on plexus occurs during difficult delivery in infants Physical exam adducted, internally rotated shoulder; pronated forearm, extended elbow (“waiter’s tip”) C5 deficiency axilllary nerve deficiency deltoid, teres minor weakness suprascapular nerve deficiency supraspinatus, infraspinatus weakness musculocutaneous nerve deficiency biceps and brachialis weakness C6 deficiency radial nerve deficiency brachioradialis, supinator weakness Prognosis best prognosis for spontaneous recovery Klumpke's Palsy (C8,T1) - Lower lesion Mechanism rare in obstetric palsy usually arm presentation with subsequent traction/abduction from trunk Physical exam deficit of all of the small muscles of the hand (ulnar and median nerves) “claw hand” wrist in extreme extension because of the unopposed wrist extensors hyperextension of MCP due to loss of hand intrinsics flexion of IP joints due to loss of hand intrinsics Prognosis poor prognosis for spontaneous recovery frequently associated with a preganglionic injury and Horner's Syndrome Total Plexus Palsy (C5-T1) Mechanism stretch, rupture, and avulsion injury Physical exam flaccid arm both motor and sensory deficits Imaging chest radiograph to look for ipsilateral hemidiaphragm paralysis from phrenic nerve injury Prognosis worst prognosis Treatment - General Nonoperative observation & daily passive exercises by parents indications first line of treatment for all obstetric brachial plexopathies while awaiting return of function key to treatment is maintaining passive motion while waiting for nerve function to return Operative microsurgical nerve grafting indications lack of antigravity biceps function between 3-9 months of age postganglionic injury with intact nerve roots with segmental injury to nerve outcomes improved outcomes are seen with shorter grafts (<10cm) nerve transfer or neurotization definition nerve transfer refers to fascicles from one nerve transferred into a nother nerve that supplies a muscle neurotization refers to placing nerve fascicles directly into a neuromuscular junction of a muscle indications lack of antigravity biceps function between 3-9 months of age preganglionic injury or avulsion of nerve roots Treatment - Shoulder Dislocation & Contractures Operative soft tissue procedures latissimus dorsi and teres major transfer (Hoffer procedure) indication persistent internal rotation contracture or external rotation weakness without glenohumeral dysplasia technique pass tendons posteriorly around humerus to create external rotation forces pectoralis major and +/- subscapularis lengthening indication to lessen the internal rotation forces may be used in conjunction with tendon transfers arthroscopic release for internal rotation contractures bony procedures proximal humeral derotation osteotomy (Wickstrom) indication persistent internal rotation contracture or external rotation weakness with glenohumeral dysplasia arthrodesis indication non-functional deltoid with good function of hand and wrist Treatment - Elbow Flexion Contracture Nonoperative serial nighttime elbow extension splinting indications for elbow flexion contracture <40 degrees outcomes prevents progression, does not correct contracture serial elbow extension casting indications for elbow flexion contracture >40 degrees Operative anterior capsular release, biceps/brachialis tendon lengthening indications for severe, persistent contracture outcomes may have high recurrence rate Treatment - Forearm Operative indications residual supination contracture of the forearm technique biceps rerouting tendon transfer intact passive passive pronation forearm osteotomy with biceps rerouting tendon transfer limited passive forearm pronation Treatment - Wrist and hand Operative indications replace function for a paralyzed muscle force is preportional to cross-sectional area of the muscle amplitude is proportional to the length of the muscle technique tendon transfers wrist drop pronator teres to ECRB loss of finger extension FCR or FCU to EDC 2-5 thumb abduction EIP to abductor pollicis brevis Complications Initial nerve inury phrenic nerve palsy if persistent may require diaphragm plication Surgical complications shoulder tendon transfers radial and axillary nerve palsies Phrenic nerve palsy if persist may require diaphragm plication Prognosis 90% of cases will resolve without intervention spontaneous recovery may occur for up to 2 years Prognostic variables for spontaneous recovery favorable Erb's Palsy complete recovery possible if biceps and deltoid are anti-gravity by 3 months early twitch biceps activity suggests a favorable outcome poor lack of biceps function by 3 months preganglionic injuries (worst prognosis) avulsions from the cord, which will not spontaneously recover motor function loss of rhomboid function (dorsal scapular nerve) elevated hemidiaphragm (phrenic nerve) Horner's syndrome (ptosis, miosis, anhydrosis) less than 10% recover spontaneous motor function C7 involvement Klumpke's Palsy