Brachial plexus injuries

brachial plexus anatomy, etiology, mechanism of injury, classifications, clinical features, diagnosis and management.
surgical management of brachial plexus

1. BRACHIAL PLEXUS INJURIES Dr. CH ADITYA DNB RESIDENT Care hospitals, H yderabad OBJECTIVES ANATOMY ETIOLOGY MECHANISM OF INJURY CLASSIFICATION CLINICAL FEATURES INVESTIGATIONS MANAGEMENT

2. ANATOMY it is a network of nerves passing through the cervico -axillary canal to reach axilla and innervates brachium (upper arm), antebrachium (forearm) and hand . Brachial plexus is a somatic nerve plexus formed by the union of anterior rami of C5,C6,C7,C8 and T1. The formation of brachial plexus begins just distal to the scalenus muscles. Function: The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb, with two exceptions: the trapezius muscle innervated by the spinal accessory nerve (CN XI) and an area of skin near the axilla innervated by the intercostobrachial nerve.

3. CLINICAL ANATOMY The plexus consists of roots, trunks, divisions , cords and branches. Roots : Lower 4 cervical (C5-8) and the 1st thoracic. Situated between the scalenus anterior and medius muscle deep to sternocleidomastoid muscle. The origin of the plexus may shift one segment either upward or downward resulting in a PRE FIXED PLEXUS or POST FIXED PLEXUS respectively. In a prefixed plexus, the contribution by C4 is large and in that from T2 is often absent. In a post fixed plexus, the contribution by T1 is large, T2 is always present, C4 is absent, and C5 is reduced in size.

4. Trunks : Derived from roots Located in the antero-inferior portion of post triangle of neck C5-6  ant primary rami unite  upper trunk. C8-T1  ant primary rami unite  lower trunk. C7 – ant primary rami continues as  middle trunk. Each trunk ends by splitting into 1) Ant. 2) Post - divisions.

5. CORDS:   it forms 3 cords The Posterior Cord is formed from the three posterior divisions of the trunks (C5-C8,T1) The Lateral Cord is the anterior divisions from the upper and middle trunks (C5-C7) The Medial Cord is simply a continuation of the anterior division of the lower trunk (C8,T1)

6. BRANCHES: Branches of the brachial plexus may be described as supraclavicular and infraclavicular . Supraclavicular branches Supraclavicular branches arise from roots or from trunks as follows : From roots 1 . Dorsal scapular nerve C5 2 . Long thoracic nerve C5, 6 (7) From trunks 1. Nerve to subclavius C5, 6 2. Suprascapular nerve C5, 6 : NOTE: SUPRASCAPULAR NERVE IS THE FIRST IMPORTANT BRANCH SEEN WHEN THE PLEXUS IS EXPLORED SUPERIOR TO THE CLAVICLE

7. Infraclavicular branches branches come from the cords, L ateral cord Lateral pectoral C5, 6, 7 Musculocutaneous C5, 6 7 Lateral root of median C(5), 6, 7 Medial cord Medial pectoral C8, T1 Medial cutaneous of forearm C8, T1 Medial cutaneous of arm C8, T1 Ulnar C(7), 8, T1 Posterior cord Upper subscapular C5, 6 Thoracodorsal C6, 7,8 Lower subscapular C5, 6 Axillary C5, 6 Radial C5, 6, 7, 8, (T1)

8. ETIOLOGY penetrating wounds Missiles Stab wounds Injuries related to birth Traction applied to the plexus during falls Vehicular accidents Sports activities and R adiation

9. In most large series, motorcycle accidents are the most common cause 70%. In 20% cases a/w rupture of subclavian or axillary artery. Spinal cord injury is reported in 2% - 5% cases. COMMON ASSOCIATED INJURIES Fractures of the proximal humerus Scapula fractures Rib fractures Clavicle fractures Fracture of the transverse process of cervical vertebrae Dislocations of the shoulder, acromioclavicular and sternoclavicular joints

10. Mechanisms of Injury to the Brachial Plexus Traction: direct blow to the shoulder with the neck laterally flexed toward the unaffected shoulder (gymnast falls on beam) B. Direct trauma : direct blow to the supraclavicular fossa over Erb’s point C. Compression: Occurs when the neck is flexed laterally toward the patient’s affected shoulder, compressing / irritating the nerves, resulting in point tenderness over involved vertebrae of affected nerve(s) ( Troub , 2001)

11. Mechanisms of Injury to the Brachial Plexus

12. CLASSIFICATION OF BRACHIAL PLEXUS INJURIES: Classification of injuries The various classifications of brachial plexus injury are as follows: 1. Leffert classification of brachial plexus injury 2. Millesi classification of brachial plexus injury 3 . Classification on anatomical location of injury 1.  Leffert classification of brachial plexus injury:  It is based on mechanism and level of injury and is as follows I  Open (usually from stabbing) II  Closed (usually from motorcycle accident) IIa  Supraclavicular

13. preganglionic: avulsion of nerve roots, usually from high speed injuries no proximal stump, no neuroma formation ( neg Tinel's ) pseudomeningocele , denervation of neck muscles are common horner's sign (ptosis, miosis , anhydrosis ) postgangionic : roots remain intact; usually from traction injuries; there are proximal stump and neuroma formation ( pos Tinel's ) deep dorsal neck muscles are intact, and pseudomeningoceles will not develop; IIb Infraclavicular Lesion: usually involves branches from the trunks (supraclavicular); function is affected based on trunk involved; III  Radiation induced IV  Obstetric IVa  Erb's (upper root) IVb   Klumpke (lower root)

14. 2. Millesi classification of brachial plexus injury :   It is mainly divided into 4 I : supraganglionic /preganglionic. II : infraganglionic /postganglionic III : trunk. IV : cord. 3. Classification on anatomical location of injury : Upper plexus palsy ( Erb’s palsy in the OBPI cases) involves C5-C6+/-C7roots. Lower plexus palsy ( Klumpke’s palsy) involves C8-T1 roots (and sometimes also C7) Total plexus lesions involve all nerve roots C5-T1

15. Lower brachial plexus injuries Upper brachial plexus injuries

16. ERB'S PARALYSIS: Site of injury:  The region of the upper trunk of the brachial plexus is called Erb's point. Injury to the upper trunk causes Erb's Paralysis. Causes of injury :  Undue separation of the head from the shoulder, which is commonly encountered in 1)birth injury 2) fall on shoulder, and 3)during anaesthesia Nerve roots involved :  Mainly C5 and partly C6. Muscles paralysed :  Mainly biceps, deltoid, brachilais and brachioradialis.Partly supraspinatus, infraspinatus and supinator

17. Deformity Arm: Hangs by the side, it is adducted and medially rotated Forearm: Extended and pronated Abduction impossible because of paralysis of deltoid & supraspinatus m/s. ER impossible because of paralysis of infraspinatus & teres minor m/s.

18. Active flexion impossible because of paralysis biceps, brachialis & brachioradialis. Paralysis of supinator m/s causes pronation deformity of forearm . The deformity is known as "Policeman's tip hand" or "Porter's tip hand".

19. KLUMPKE’S PALSY Site of injury :  Lower trunk of the brachial plexus. Cause of injury :  Undue abduction of the arm, as in clutching something with the hand after a fall from a height, or sometimes in birth injury. Nerve roots involved :  Mainly T1 and partly C8. Muscles paralysed : Intrinsic muscles of the hand (T1) Ulnar flexors of the wrist and fingers (C8). Deformity:   (position of the hand): claw hand due to the unopposed action of the long flexors and extensors of the fingers. in a claw hand there is hyperextension at the metacarpophalangeal joints and flexion at the interphalangeal joints.

20. Disability: Claw hand Cutaneous anaesthesia and analgesia in a narrow zone along the ulnar border of the forearm and hand. Horner's syndrome : ptosis, miosis, anhydrosis, enophthalmos and loss of ciliospinal reflex- may be associated. This  is because of injury to sympathetic fibres to the head and neck that leave the spinal cord through nerve T1. Vasomotor changes : The skin areas with sensory loss is warmer due to arteriolar dilation. skin is dry due to the absence of sweating as there is loss of sympathetic activity. Tropic changes : Long standing case of paralysis leads to dry and scaly skin.The nails crack easily with atrophy of the pulp of fingers.

21. Clinical features : History : The mechanism of injury should be considered. Birth injury : Usually 5th and 6th root. Motor cycle accidents. Stab and bullet wounds . Symptoms vary depending upon the type and location of the injury to the brachial plexus. The most common symptoms of BPI include: -Weakness or numbness -Loss of sensation -Loss of movement (paralysis) -Pain .

22. CLINICAL FEATURES The pain from brachial plexus injuries results from injury to the spinal cord where the nerve rootlets are avulsed from the cord. This pain is neuropathic in nature. The pain can last for a very long time. Brachial plexus injuries that occur at the level of the spinal cord often produce greater pain than injuries more distant from the spinal cord . In addition, injuries nearer the spinal cord may cause a burning numbness, which is called paresthesias or dysesthesias .

23. Physical examination : Examination of all nerve groups controlled by the brachial plexus to identify the specific location of the nerve injury and its severity. In addition, some patients display specific signs that help determine the location of the nerve injury: Narrowing of the eye pupils, drooping of the eyelid, and lack of ability for the face to sweat (Horner's syndrome) is a sign that the injury is close to the spinal cord. A shooting nerve-like pain on taping along the affected nerves ( Tinel sign) suggests an injury farther from the spinal cord. Over time, if the location of the Tinel sign moves down the arm toward the hand, it is a sign that the injury is repairing itself. During the physical examination , assess the arm and shoulder for stability and range of motion

24. INVESTIGATIONS Imaging Studies Electromyogram Nerve Conduction Velocity Intraoperative Nerve Action Potential Myelography CT scan for any tumours MRI

25. Imaging studies : X-ray of cervical spine : Fracture of lateral masses of cervical vertebrae are strongly associated with pre-ganglionic injuries. Chest x-ray : May show 1st and 2nd rib fracture or an elevated hemidiaphragm , which denotes phrenic nerve paralysis and proximal injury to upper plexus. Fractures of scapula and clavicle and Humerus may indicate infraclavicular plexus injuries.

26. INVESTIGATIONS EMG : Most important use of EMG studies is for serial evaluation of injury to search for signs of re innervation. A decreased in number of fibrillation potentials and positive sharp potentials  typically seen in dennervated muscles  regenerating axons have reached the motor end plates. The appearance of prolonged, polyphasic and low-amp indicated  re-innervation. Seen several weeks before the onset of voluntary muscle contraction and signify that a further period of observation is in order.

27. Intra operative nerve action potential (NAP) : This study is performed during surgical exploration of the plexus , which is usually done 3-4 months after injury. If a nerve action potential can be recorded. Substantial number of regenerating axons have traversed the lesion site. Conversely if an action potential cannot be elicited  the abnormal segment is resected because spontaneous recovery is likely to be poor. NAP is best for evaluating a neuroma in continuity. If an NAP can be transmitted across the area of injury, the patient has 93% chance of useful motor function will develop in the muscles supplied by that nerve.

28. CT Myelography : If plexus injury is strongly suspected a myelogram and subsequent CT scan should be obtained 2-3 months after injury . It may be inaccurate early after the injury because clotted blood may occlude the opening into the pseudomeningocele . A delay of 6-12 weeks is recommended before myelogram is advised. Advantages: - detect partial root avulsion -excellent visualization of bony structures -no CSF flow artifacts and - multiplanar reconstruction. Disadvantages: - high radiation dose -poor visualization of lower brachial plexus due to bony artifacts .

29. CT myelogram showing a normal brachial plexus (left) and injured brachial plexus (right)

30. Nagano et al . classified myelographic findings into six types; N, A1, A2, A3, D, and M . N is a normal shadow ; A1 is a slightly abnormal root sleeve shadow in which shadows of roots and rootlets can be recognized but appear different from those on the unaffected side; A2 is obliteration of the tip of the root sleeve with the shadows of roots or rootlets visible ; A3 is obliteration of the tip of the root sleeve with no shadows of roots or rootlets visible ; D is a defect instead of a root sleeve shadow; and M is a traumatic meningocele .

31. N is the sign of normality or a postganglionic lesion. A1 is observed in either a preganglionic or a postganglionic lesion; thus, detailed evaluation with CT myelography is necessary for this kind of finding . A2, A3, D, and M are indicative of a preganglionic lesion.  A traumatic meningocele is a valuable sign of a preganglionic lesion, although it is not pathognomonic.

32. CONVENTIONAL MRI MRI provides additional anatomic and physiologic information on injuries . 1. Signal intensity changes in the spinal cord 2. Enhancement of nerve roots and 3. Enhancement of paraspinal muscles 

33. Signal intensity changes in the spinal cord Hyperintense areas on T2-weighted images suggest edema in the acute phase and myelomalacia in the chronic phase. Hypointense lesions on T2-weighted images reflect hemosiderin deposition on account of hemorrhage .

34. 2. Enhancement of nerve roots Enhancement of intradural nerve roots and root stumps suggests functional impairment of nerve roots despite morphologic continuity Breakdown of the blood-nerve barrier and dilatation of radicular veins are postulated as the mechanisms of intradural nerve root enhancement.

35. 3. Enhancement of paraspinal muscles Abnormal enhancement of paraspinal muscles is an accurate indirect sign of root avulsion injury. Denervated muscles show enhancement as early as 24 hours after a nerve is injured. The presumed mechanisms for muscle enhancement are 1. dilatation of the vascular bed and 2. enlargement of the extracellular space.

36. Nerve root avulsion. Axial T2-weighted ( A ) and coronal MIP 3D STIR SPACE ( B ) images show the avulsed left T1 nerve root ( large arrows ) and C8 nerve root ( small arrow ) with pseudomeningocele formation

37. MANAGEMENT Closed Brachial Plexus Injury Open Brachial Plexus Injury

38. Closed injury In the case of closed BPI wounds and when there are no other emergent injuries, surgical exploration and recovery may not take place immediately. Recommendations include managing pain, and starting rehabilitation .

39. Closed Brachial Plexus Injury Barnes divided Upper & Lower Plexuses injuries caused by traction into four groups 1)Injuries at C5 & C6 2)Injuries at C5,C6 & C7 3)Degenerative lesions of entire plexus 4)Injuries at C7,C8 & T1 (rare)

40. Barnes reported that spontaneous recovery in group 1 & 2 cases But in case of Degenerative plexus injuries there is partial recovery. EMG should be done at 3 to 4 wks. At 6 to 8wks additional studies like myelography & axon reflex evaluation can be done if return of functions not seen. Exploration is justified at 3 to 6 months after injury if function has not returned.

41. OPEN INJURIES Open wounds in BPI are uncommon and vary from small penetrating injuries to high energy injuries. INDICATIONS OF SURGERY : Injuries caused by sharp objects or missiles. When patient seen soon after injury & pt's general condition permits exploration & primary repair can be done When patient not seen soon after injury but only after initial management, It is best to wait for wound healing & stabilization of any other injuries.

42. During this period locate neurological deficit for level of injury. EMG performed 3 to 4 wks after injury . Exploration of plexus & neurorrhaphy, autogenous interfascicular nerve grafting or neurolysis is indicated 3 to 6wks after injury . Motor function recovered to a grade of 3 or better in half of pts . Best results obtained in upper trunk & lateral cord & posterior cord injuries . Poor prognosis can be expected in lower trunk injuries.

43. CONSERVATIVE TREATMENT AIMS: to maintain the range of motion of the extremity to strengthen the remaining functional muscles to protect the denervated dermatomes, and to manage pain .

44. Pain management: Significant pain is observed in complete palsy especially in root avulsions. Pain Is excruciating and exhausting for the patient but it can affect the rehabilitation procedure . NSAIDs and opioid drugs useful during the first stages but do not appear to help with neuropathic pain, which requires careful use of antiepileptic drugs (gabapentin and carbamazepine) or antidepressants such as amitriptyline. About 30% of patients report significant pain relief with this type of treatment. 

45. SURGICAL GOALS In order of priority as follows: 1)Restoration of elbow flexion 2)Restoration of shoulder abduction 3)Restoration of sensation of medial border of forearm & hand.

46. Depending on extent of injury various surgical techniques may be required: Primary neurorrhaphy Neurolysis Nerve grafting Neurotization

47. NEUROLYSIS When the nerve lesion is in continuity, neurolysis may help. It is of great importance to maintain the interfascicular structure and the nerve sheath . Because of the risk of vascular damage interfascicular neurolysis not done. instead an anterior epineurectomy is performed, excising the fibrous tissue. Use of direct nerve stimulation before and after neurolysis helps us demonstrate the improvement in nerve conductance.

48. NERVE GRAFTING Nerve grafting is the predominant technique for clear cut injuries with a healthy proximal stump and with no axial damage . The outcome is influenced by the length of the nerve graft the presence of scar tissue at the wound site the number of grafts used the presence of a healthy proximal stump available for grafting and the nerve gap to be covered. 

49. The sural nerve, the sensory branch of ulnar nerve, and the medial cutaneous nerve of the forearm are the usual donor nerves . Generally, use of nerve grafts shorter than 10 cm results in better functional and clinical outcomes compared with longer grafts

50. NEUROTIZATION This type of procedure is used for preganglionic root injury The nerve transfer may be extraplexus or intraplexus . Intraplexus transfer options include intact nerve roots. Other choices include the use of the medial thoracic nerve and inferior medial cord/ulnar nerve. Oberlin et al. described nerve transfer to the biceps muscle using part of the ulnar nerve for C5-C6 avulsion of the brachial plexus Extraplexus transfer options include the use of intercostal and spinal accessory nerves. The phrenic nerve and deep motor branches of the cervical plexus (C3-C4) may be used as donor nerves.

51. In ROOT avulsion of upper plexus in which no proximal neural stump is available for nerve grafting, neurotization between intercostal nerves or FCU motor fascicles of ulnar nerve & musculocutaneous nerve to restore the ELBOW FLEXION may be considered .

52. NEUROTIZATION of the suprascapular nerve using the spinal accessory nerve and neurotization of the axillary nerve with fascicles of radial nerve innervating the lateral, medial, or long head of triceps can be used to restore SHOULDER ABDUCTION AND EXTERNAL ROTATION

53. After Brachial plexus repair & regeneration 12 to 18 mths required to determine extent of neural regeneration. If recovery inadequate Peripheral reconstruction considered

54.   Secondary Operations In the absence of spontaneous recovery or when the first surgical procedure does not provide satisfactory outcomes then a second operation may be required . In such cases there should be specific signs of neurological denervation or no possibility of neurological recovery, or sufficient time should have passed with no functional improvement. Secondary options include 1. Arthrodesis 2. Tendon transfer and 3. Functional free muscle transplantation are favoured treatment options.

55. ARTHRODESIS INDICATIONS In complete brachial plexus traumatic injuries unstable and painful shoulders When planning shoulder arthrodesis certain parameters should be taken into consideration . good thoracic-shoulder functionality . the mobility of the peripheral hand is important as shoulder arthrodesis has no clinical effect on a paralytic hand. The acromioclavicular joint, sterno-clavicular joint, and scapulothoracic joint should be intact. Any dysfunction may affect the success of arthrodesis. NOTE : The shoulder should be fused with only 20 degrees of abduction, 30 degrees flexion, and 30 degrees of internal rotation to allow the patient to be independent in his daily life with a mean range of 60 degrees abduction and flexion through the scapulothoracic joint.

56. TENDON TRANSFERS Tendon transfers are useful in restoring upper extremity function after BPI . An absolute indication for tendon transfer is upper or lower brachial plexus traumatic injury with only partial paralysis.

57. TENDON TRANSFERS Many tendon transfer techniques have been described for treating partial shoulder paralysis. the most common procedures are the following : 1.Trapezius to deltoid transfer as described by Elhassan et al . in 2000 to restore abduction of the shoulder 2.Latissimus dorsi transfer as described by L’ Episcopo , to improve external rotation. 3. Anterior transfer of the posterior branch of the deltoid muscle to restore nonfunctional anterior segment .

58. Restoration of elbow flexion The surgical goal is to restore good muscle strength through a range of elbow motion (30 to 130 degrees ). The most commonly used procedures are as follows: i)transfer of the common origin of the flexor forearm muscles to a proximal section as described by Steindler (1918) . The Steindler technique may lead to disappointing outcomes such as elbow stiffness or over pronation; (ii)transfer of latissimus dorsi muscle to the tendon of the biceps brachialis provides great muscle strength, but this muscle is often denervated (iii)transfer of pectoralis major brachial branch tendon to brachial biceps (Clark technique). A fused shoulder is required for the best postoperative result; (iv)transfer of triceps tendon to biceps provides good results

59. Anterior shoulder release: First described by Fairbanks & modified by Sever Main indication is iatrogenic internal rotation contracture & imbalance between shoulder internal & external rotation.

60. Guidelines for arthroscopic treatment of contractures & deformity sec to brachial plexus birth palsy

61. RECOVERY AND REHABILITATION Because nerve regeneration occurs slowly at a rate of approximately 1 mm/day, recovery from a brachial plexus injury takes time, and patients may not experience results for several months. A positive mindset and the support of family, friends, and healthcare professionals are important to recovery and rehabilitation. During this recovery process, occupational therapists teach patients how to use the unaffected arm to perform daily activities like eating and personal hygiene .

62. Physical therapy of the shoulder, elbow, wrist, and fingers involves specific exercises to prevent stiffness, contractures, or muscle atrophy . A physical therapist can also recommend assistive devices, such as splinting or supportive bracing to help support a limp arm and joints. Compression gloves and sleeves may be used to prevent swelling in the affected arm, which can lead to pain and joint contractures. Pain may be managed with medications, therapy, and assistive devices. In addition, patients will require healthy coping skills in order to make adjustments in their lives.

63. THANK YOU

64. OBERLIN TECHNIQUE Christophe Oberlin described transfer of one or more ulnar nerve fascicles to the motor branches of the biceps muscle . This is performed to restore elbow flexion in patients who have an irreparable upper trunk injury or avulsion, and an intact lower trunk . Careful selection of ulnar nerve fascicles using intraoperative nerve stimulation enables one to perform this transfer without a donor motor or sensory deficit . Technique  A 15-cm incision is made along the medial arm beginning at the pectoralis and coursing distally along the neurovascular bundle. The biceps fascia is opened and the musculocutaneous nerve identified. The motor branches to both heads of the biceps are identified approximately 12 cm distal to the acromion and stimulated to ensure complete denervation;

65. the branches are traced proximally where they usually coalesce into a single motor branch from the parent musculocutaneous nerve, and then divided sharply for transfer to the ulnar nerve. The ulnar nerve is identified by external neurolysis , and the epineurium is opened. Several fascicles of the ulnar nerve are chosen 3–4 cm distal to the level of the MC branch to the biceps and stimulated with a portable nerve stimulation unit. A single large fascicle can usually be identified to produce maximal contraction of the flexor carpi ulnaris without significant contraction of the ulnar intrinsic muscles. This fascicle (or fascicles) are divided far enough distally to transfer directly to the motor branch( es ) of the musculocutaneous nerve .

66. Ulnar nerve fascicle was transferred to the musculocutaneous nerve (Oberlin transfer) to achieve biceps function