Introduction to Nerve Complications After Bone Trauma
PTA 104 Orthopedic Dysfunctions

Instructional Use Statement

The following information is used for instructional purposes for students enrolled in the Physical Therapist Assistant Program at Lane Community College. It is not intended for commercial use or distribution or commercial purposes. It is not intended to serve as medical advice or treatment.

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Nerve Complications Post-Bone Trauma

Introduction

Nerve injury can result following a fracture and may result in most disabling symptoms well after the bone tissue is healed. Injury to nerve tissue may be temporary or permanent. Specific interventions for management of upper and motor neuron conditions will be covered in PTA 204/204L. The purpose of this lecture is to introduce the etiology of nerve disorders as it related to fracture diagnoses and to reinforce how the phases of healing discussed for conditions of orthopedic conditions/trauma relates to management of peripheral nerve conditions

Objectives

Describe the mechanisms of nerve injury post-fracture
Describe factors which influence the rate and extent of recovery from nerve injury
Compare and contrast general nerve injury management strategies across the three phases of healing
Describe how the degree of nerve injury is predictive of nerve recovery
Recognize signs and symptoms of selected peripheral nerve injuries and entrapment syndromes

Nerve Injury Mechanisms

compression

direct compression from displaced bone can injury neighboring nerves
direct compression from hemorrhage post-fracture
direct compression from prolonged positioning/immobility post-fracture
soft-tissue inflammation/overuse can increase compression to nerve tissue

surgical complications

peripheral nerves for superficial sensation and sensorimotor function may be stretched or cut during operative procedures

Nerve Injury Classification

First degree - temporary demyelination - recovery expected in 12 weeks
Second degree - associated with more severe trauma or prolonged compression, includes more extensive demyelination and axonal degeneration; regeneration is likely and may take 6 months to a year or more
Third degree - extent of nerve injury and demyelination is extensive - regeneration is not likely
Fourth degree - significant nerve injury and extensive scar formation prevents any regeneration below scar area; surgical interventions for recovering function
Fifth degree - complete nerve transection; surgical intervention to recover function
Sixth degree - describes a combination of varying levels of function within a nerve, which may require surgical interventions to restore function

Nerve Injury Recovery

Nature of injury

nerve injuries that are proximal (i.e. closer to the nerve root) affect more structure and result in greater loss of function
nerve injuries that are proximal are slower to recover due to regeneration times (0.5mm to 1 in./day) and regeneration may be incomplete

Timing of repair

complete laceration of nerves require surgical intervention: surgical success rate depends on timing of surgery since injury and location of nerve

Age and motivation

neuroplasticity and adaptability of motor and pre-motor planning and sensory reintegration is higher in the younger population
repeated initiation, practice, feedback optimizes ability to redevelop sensorimotor pathways and motor function

Overview of peripheral nerve injury and entrapment

Nerve entrapment in the upper and lower extremities can be temporary or long-standing. Conditions such as obesity and pregnancy where there is increase fluid or body weight on nerves can interfere with nerve gliding. Surgical interventions and subsequent scar formation can also entrap nerves, resulting in chronic nerve symptoms, pain, and loss of function.

In some cases, patients consent to surgery to release the nerve or to transfer nerves to restore function in affected sensory and motor areas.

Upper Extremity Peripheral Nerve Injuries

Upper extremity nerve injuries are more common than lower extremity. Compression and traction (stretching) forces to components of the brachial plexus can result in pain, loss of sensation, and loss of motor function. Note how the brachial plexus originates from C5-T1 and then forms a series of overlapping trunks, divisions, and cords, before branching into peripheral nerves. Proximal compression can result in significant neurovascular syndromes, which may requires surgical releases to preserve nerve function and circulation. Neal and Fields (2010) noted, "risk factors include a superficial position, a long course through an area at high risk for trauma, and a narrow path through a bony canal"

https://commons.wikimedia.org/wiki/File:Brachial_plexus_anterior_view_nerves.JPG;

https://commons.wikimedia.org/wiki/File:Wikipedia_medical_illustration_thoracic_outlet_syndrome_brachial_plexus_anatomy_with_labels.jpg

Upper Extremity Nerve Injury Signs and Symptoms

Nerve	Injury Risk	Presentation
Axillary	Stretch during abduction; glenohumeral dislocation; compression in axilla (e.g. misuse of crutches)	Weakness in teres minor and deltoid
Long Thoracic	Sudden upper extremity traction; shoulder depression with contralateral lateral cervical flexion, sustained compression ("Backpacker's syndrome)	scapular winging
Suprascapular	Throwing athletes, trauma, clavicle fracture	supraspinatus weakness, atrophy and tenderness, pain with horizontal adduction,
Median	Elbow, forearm, and wrist overuse or injury	weak and painful grip; sensory changes in hand
Musculocutaneous	Shoulder dislocation; biceps injury; hypertrophy of coracobrachialis	shoulder and elbow flexion weakness
Radial	Proximal humerus fracture; elbow fracture or dislocation; "Saturday Night Palsy" when passing out from alcohol use results in prolonged compression on chair or bar	weakness in elbow flexion and wrist extension
Ulnar	Elbow dislocation or prolonged posterior elbow compression; repetitive throwing	weakness in the ulnar side of the hand and interossei

Lower Extremity Nerve Entrapment Signs and Symptoms

Nerve	Injury Risk	Presentation
ilioinguinal (T12-L1)	Lower abdominal surgery; orthopedic surgery (iliac bone harvesting for bone graft), pregnancy	pain in groin and medial inner thigh, may radiate to genital areas
lateral femoral cutaneous nerve (L1-L3)	tight clothing (e.g. jeans), pregnancy, trauma to ASIS	also known as "meralgia paresthetica" burning, coldness, or lightning like pain on lateral thigh
femoral nerve (L2-4)	trauma (surgical or other), pelvic fracture, acute hyperextension of hip, diabetes (neuropathy), tumors	numbness, tingling and burning in the thigh, quadriceps weakness; difficulty managing stairs, feeling like knee will buckle
sciatic nerve (L4-S1)	hypertrophy of piriformis, direct trauma to SI or gluteals, hip flexion contracture, excessive hamstring exercise	also known as "piriformis syndrome" Numbness, tingling, and weakness in the posterior hip and extend down posteriorly to the toes
tibial nerve	Rheumatoid arthritis, Baker's cyst (posterior knee), diabetes, tight-fitting shoes, pronation or pes planus	also known as "tarsal tunnel syndrome" when involves the posterior tibial nerve sensation changes and weakness to the bottom of the foot and toes; weakness in plantar flexion and eversion; pain with weight bearing

https://en.wikipedia.org/wiki/Piriformis_syndrome

Interventions for Peripheral Nerve Conditions

Acute Stage

Immobilization and interventions for controlling inflammation and reducing swelling is the primary focus. Gentle AROM in unaffected areas and in pain-free ranges to help maintain nerve mobility above and below the injury is introduced. Care is taken to avoid positions and motions that increase nerve symptoms (pain and sensory changes). Close monitoring of skin for lesions, such as blisters to rule out possible infectious or systemic sources of nerve function loss.

Wrist and hand conditions: Avoid hot, cold or sharp objects; Do not prolong grasp positions, change hands frequently; Utilize built up handles to distribute pressure

Lower extremity conditions: Wear well fitting, protective shoes, have closed toes and heels; Inspect feet daily for signs of pressure or abrasion; Do not walk barefoot; Frequently shift weight during all standing activities

Recovery stage

The nerve is demonstrating recovery through increasing sensory activity or muscle activity. Motor retraining begins with isometrics in shortened positions and electrical stimulation to promote motor recovery is introduced.

Desensitization may be used by application of various sensory inputs to the affected area, such as placing soft and rough textures on the affected skin.

Discrimination retraining may be used to reteach differentiating 2 points of simultaneous contact. Begin with visual input, then remove it.

Persistent/chronic stage

Interventions are largely compensatory, such as using assistive devices, alternative movement strategies, activity modification, and patient education in activities that may increase strain to the nerve. Interventions for these more complex conditions are addressed in PTA 204/204L; may include interventions, such as the use of a mirror box or guided imagery for pain management and sensory reorganization.

End of Lesson

Congratulations - you've finished your final lecture as a first year SPTA!