We use these guidelines if you received a work-related injury and are curious about the effect of “Scheduled Loss of Use (SLU) on your central nervous system condition, peripheral nerve injury, or entrapment/compression neuropathy. Then, you could be eligible for a compensation payment determined by the Workers’ Compensation Board’s regulations.
Our SLU report will conclude that you have permanently lost function in the injured body part due to your work-related accident. The determination of impairment is based on New York state Workers’ Compensation guidelines.
Central Nervous System – Cranial Nerves
A cribriform plate fracture or perforating cranial nerve filament injury may cause anosmia of the frontal trauma (coup or contra coup). An upper respiratory infection is the most likely cause of anosmia and may clinically appear as an ethmoid fracture.
Third, Fourth & Sixth Nerve
Third nerve involvement may result in trauma-related anisocoria, lid droop (ptosis), ciliary ganglion branches (sphincter of the iris) with dilation, and reflex iridoplegia. Complete third nerve involvement may cause outward/downward turning of the eye and a dilated pupil.
Fourth nerve involvement causes diplopia, a downward eye turning (superior oblique palsy).
Sixth nerve palsy causes weakness, paralysis, and convergent squint abduction. In addition, a permanent facial disfigurement may occur due to corneal clouding, aphakia, or other eye injuries.
The motor function of the fifth nerve is primarily responsible for biting function through the masseter’s muscle. Trauma-related basal skull fracture may associate with any of the three branches of the fifth nerve (ophthalmic, maxillary, or mandibular). Trigeminal neuralgia (douloureux) etiology is not entirely known. Unfortunately, injuries to the fifth nerve can result in disability; it is not typically compensable.
The facial (seventh) nerve may produce upper neck or traumatic facial injuries with a volitional loss and emotional movement on the affected side. For example, patients may not elevate an eyebrow, frown, close their eyes, show teeth, whistle, or purse their lips. In addition, the Bell’s phenomenon causes the globe to roll upwards when trying to close the eye.
Drinking causes fluid spills from the affected side. Hyperacusis may occur will an affected stapedius muscle. The etiology of Bell’s Palsy is not entirely known, but possibly stylomastoid foramen swelling. Bell’s Palsy may occasionally happen with viral eruptions, such as Herpes Zoster in the external auditory canal, called Ramsey Hunt Syndrome.
However, it is not a compensable injury unless a facial or appropriate neck injury is present. Up to 2/3 of the ipsilateral tongue may result in a loss of taste.
Components of the eighth nerve include cochlear (auditory) and vestibular (equilibrium). Unilateral loss is partially disabling, whereas bilateral loss is extremely disabling due to communication impairment. Therefore, an eighth nerve injury may result in a severe industrial-related disability.
Ninth, Tenth, and Eleventh Nerve
Injuries to the ninth, tenth and eleventh nerves are not typically compensable.
Instead of trauma to the twelfth nerve, brainstem infarction may cause unilateral loss and not typically disabling.
Peripheral Nervous System
Excessive stretching and compression, for example, due to carrying heavy weights, being placed in a prolonged anesthetic position, or being a gunshot victim, may cause brachial plexus injury. However, cervical nerve root avulsion may present similarly in a clinical setting.
In addition, a complete brachial plexopathy may occur because of vehicular trauma, including arm paralysis and total absent reflexes.
Temporary total disability may create a severe loss of function and pain due to severe brachial plexopathy. Therefore, we will wait for at least two years to evaluate deficits and permanent disability, then conduct a loss schedule because a milder involvement may result in only a partial disability.
An upper brachial plexopathy affects the biceps, deltoid, supinator longus, brachialis, supraspinatus, infraspinatus, and rhomboid muscles. In addition, it may create the arm to become side hanging with an internal rotation.
However, hand motion is not affected, and the prognosis is good, but the occasional return of function is incomplete. Therefore, we will reevaluate after two years to determine the recovery of function and create an amenable schedule loss of the arm.
Surgery or falling on the affected arm may cause lower brachial plexopathy with weakness, small hand muscle wasting, and typically allow a high schedule of loss of the use of the hand.
We will wait at least two years to provide a final adjustment of a brachial plexopathy, despite having a rib section. A partial disability and classification may become necessary if the patient has persistent severe weakness and intractable pain.
Thoracic Outlet Syndrome
Anterior scalene hyperplasia and hyperabduction may develop thoracic outlet syndrome. In addition, an abnormal cervical rib that arises from the seventh cervical vertebra could laterally extend between the anterior and medial scalene muscles.
As a result, the abnormal cervical rib disturbs the outlet and causes brachial plexus or subclavian artery compression. Unfortunately, only 1/5% of the population have cervical ribs, and only ten percent have symptoms. Causes of cervical ribs include sagging shoulders and occupational activities, often characterized by pain and paresthesia.
Therefore, we rely on Adson’s signs for making a diagnosis. According to the following technique, determining the subclavian artery by the scalenus anticus muscle includes having the patient seated with elbows at the sides and extending the neck.
Total obliteration will reveal a positive test performance by turning the chin downwards toward the affected side during deep inspiration while palpating the radial pulse. Nerve conduction studies and angiography may confuse diagnosis with cervical discs, carpal tunnel syndrome, or ulnar nerve compression at the elbow.
However, if corrected via surgery or other treatment modalities, the injury may become amenable to schedule loss of arm use, and mild symptoms and neurological deficits remain. Therefore, we will consider classification if symptoms and deficits are severe and disabling.
Entrapment and Compression Neuropathies
Entrapment and compression neuropathies pathophysiology include a passing and trapped nerve through a tight canal, most observable during constant movement or pressure. Strangulation of the nerve causes ischemic damage and significantly thickened epi and perineurium. Symptoms involve sensory than motor function and often fluctuate with activity and rest.
Median Nerve – Carpal Tunnel Syndrome
Carpal tunnel syndrome is the most common upper limb peripheral nerve entrapment syndrome. Median nerve compression due to synovium thickening around flexor wrist tendons is likely the cause, including hematoma, callus formation, and malunited fractures.
In addition, patients often have symptoms of thenar eminence atrophy, tingling, numbness of the first three and a half fingers, opposition thumb weakness, positive Tinel’s test, and a positive Phalen’s test. Typically, a patient will receive an average 10-20% loss schedule of use of the hand is usually provided to patients with carpal tunnel syndrome, with or without compression. However, we will consider classification if symptoms persist, and the condition becomes disabling.
Ulnar Nerve – Cubital Tunnel Syndrome
Direct ulnar nerve trauma at the elbow is highly likely due to the superficial position and is only covered by fascia and skin. Trauma may be one remarkable or multiple minor traumatic incidents, such as constant elbow pressure.
Patients may incur pressure during anesthesia, but this usually results in an injury by tightly pressing against the ulnar groove. As a result, the ulnar nerve becomes tethered and passes through the two carpi ulnaris heads. Patients often experience signs and symptoms including:
Burning pain and hypesthesia of the ring and small fingers
Unable to separate the fingers due to interosseous weakness, a significant intrinsic hand muscle portion of the affected hand
Cocked ring and small fingers due to flexor digitorum profundus weakness at the MCP joint (hyperextension)
Flattening of the hypothenar eminence due to bulk loss
The preferred treatment is ulnar nerve transposition. Therefore, we will utilize a schedule loss arm for ulnar nerve entrapment at the elbow and accompanying elbow deficits. In addition, we will schedule a loss of use of the hand if neurological and motion deficits occur in the hands and fingers.
Direct, forceful trauma against the hypothenar eminence base due to its location on a thinly padded bone may result in an ulnar nerve wrist injury. The cause may be a repetitive industrial force, such as pliers or a screwdriver, or other repetitive trauma, including using a cane, crutches, or splint pressure.
Patients will report weakness of pinching power of the thumb and sensory loss within the ring and small fingers.
Anterior Interosseous (Pronator Teres Syndrome)
Pronator teres syndrome may develop from compression of the median nerve passing through the heads of the pronator teres muscles.
Etiology: Direct trauma from a heavy blow to the upper forearm, causing area reactive muscle swelling due to compression of the median nerve against the sublimis edge. Pronator muscle hypertrophy tautens the sublimis edge and compresses the median nerve, usually due to an occult trauma, including forcefully repeated pronation and forceful finger flexion.
As a result, patients will develop sensory loss over the radial side of the palm, palmar side of the thumb, index, middle, and radial half of the ring finger.
A wrist pronation and IP joint of the thumb flexion inability comprise motor findings. However, thenar atrophy is not as severe as reported with carpal tunnel syndrome. Therefore, we utilize a schedule loss of use of the hand depending on motor and sensory deficits.
A profound neuropathy of the muscular branch of the radial nerve involves the posterior interosseous nerve syndrome with a manifestation of two distinct entities, motor syndrome and a rarer pain syndrome (radial tunnel syndrome, resistant tennis elbow).
Etiology: Compression by a tumor, ganglia, elbow synovitis, or trauma, such as elbow dislocation, ulnar fracture with radial head dislocation, and a radial head fracture. Injury of the posterior interosseous nerve by compression plates used during open reduction of proximal radius fractures.
As a result, nerve compression typically occurs at the entrance point to the supinator muscle beneath the arcade of Frohse.
Clinical features include complete or partial muscle weakness supplied by the posterior interosseous nerve or nerves of the extensor carpi radialis, extensor digitorum communis, extensor indicis propius, abductor policis longus, brevis, and extensor policis longus.
In addition, patients report extension weakness within the wrist and a radial deviation. In addition, extension weakness of the fingers and thumb MCP joints and the radial thumb abduction weakness.
Criteria for schedule loss of use of the hands include any residual neurological and functional deficit. However, suppose we determine that the elbow joint causes the deficiency. In that case, the schedule loss pertains to the arms.
The lateral femoral cutaneous nerve is often vulnerable to neuropathic entrapment within the region of the superior anterior spine, passing through the lateral end of the inguinal ligament and considered the binding point of the nerve.
However, the nerve becomes tensed against the entrapment point during extremity adduction. As a result, Neuropathy, burning pain, and hyperaesthesia develop over the anterolateral thigh.
Etiology: Direct trauma within the area or an anterior ilium fracture. A shortened limb and a pelvic tilt may develop, such as post-hip replacement, causing adduction of the contralateral hip that stretches the deep fascia and nerve against the entrapment point.
However, patients who perform secretarial work and sit with their legs crossed over prolonged periods may experience different symptoms.
Workers’ compensation claims for meralgia paresthetica are uncommon but possibly amenable for a scheduled loss of use of the leg for the residual sensory deficit.
Tarsal Tunnel Syndrome (Posterior Tibial Entrapment)
Tarsal tunnel syndrome may develop behind and directly below the medial malleolus. The nerve accompanies posterior tibialis, flexor hallucis longus, and flexor digitorum longus muscle tendons.
The lancinate ligament covers the structure and creates an osseofibrous tunnel. As a result, tenosynovitis within the area may create a swollen space that acts as a tarsal tunnel nerve compression lesion.
Clinical features include burning pain of the toes and soles and primary heel pain involving calcaneal branches. In addition, referred pain can develop along the sciatic axis toward the buttock, where reviewing medical history may produce relevant trauma to the site. In addition, MTP joints of all the toes may show flexion impairment.
Pain may distribute to the posterior tibial nerve when applying nerve pressure. However, alleviate symptoms by holding the heel in several positions and obtain treatment by severing the flexor retinaculum.
Workers’ Compensation claims frequently schedule tarsal tunnel syndrome, surgical or non-surgical. Tarsal tunnel syndrome may become amenable to a schedule of loss of the use of the foot depending on residual motion and neurological deficits.
Plantar (Morton’s Metatarsalgia)
Metatarsophalangeal joint hyperextension may develop entrapment and cause pain between the third and fourth toes (Morton’s neuroma). Symptoms include anesthesia at the tips of the toes and interdigital nerve tenderness when crossing the deep, transverse ligament.
In addition, nerves arise from the soles toward the more dorsal termination of the toes and become activated when hyperextending the MTP joints against the transverse ligament. An initial radiating pain into the third and fourth toes occurs while walking and then spontaneously at night.
We use a schedule loss of use of the foot for Morton’s metatarsalgia.
Complications of Plexus and Peripheral Nerve Injury
Sensory radiculopathy pain may include the sclerotome (muscle, fascia, periosteum, and bone), leading to secondary joint changes and immobilization, such as frozen shoulder complications of cervical spondylosis.
Please refer to your state’s Workers’ Compensation Board website or speak with your Workers’ Compensation attorney for more information