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Peripheral Nerve Injury and Entrapment

  1. What are peripheral nerves?
  2. What the causes of peripheral nerve injury (PNI)?
  3. How do peripheral nerves become trapped?
  4. What are the symptoms of peripheral nerve injury?
  5. How do we diagnose peripheral nerve injuries (PNIs)?
  6. How do we treat PNIs?
  7. The role of rehabilitation and therapy in the treatment of PNIs

What are peripheral nerves?

THE NERVOUS SYSTEM BROADLY CONSISTS OF 2 TYPES OF NERVES.

  • Central Nervous System. These are nerves that are in the brain itself or the spinal cord. Any injury or illness to the brain and spinal cord is labelled as a central nervous system injury. This may occur through trauma, or medical causes such as stroke or multiple sclerosis. Central nervous system injuries often have complex medical requirements and present very differently to peripheral nervous system injuries.
  • Peripheral Nervous System. As soon as nerves leave the spinal cord, they are termed peripheral nerves. There are 3 types of peripheral nerves.
    • Sensory nerves: These nerves receive sensory stimuli from the skin and communicate information back to the spinal cord, which in turn passes the information on to the brain (via the central nervous system).
    • Motor nerves: Motor nerves take signals that produce movement, from the brain and spinal cord to the muscles, stimulating them to contract.
    • Autonomic nerves: These nerves control involuntary body functions such as heart rate, blood pressure and gut motility.

IT IS IMPORTANT NOT TO CONFUSE CENTRAL AND PERIPHERAL NERVE INJURIES. THEY HAVE DIFFERENT CAUSES, TREATMENTS AND REHABILITATION STRATEGIES.

peripheral nerves

What the causes of peripheral nerve injury (PNI)?

Peripheral Nerves can become injured in several ways.

  • ENTRAPMENT. Nerves that have been trapped or compressed for too long can become injured. It is therefore important to release trapped nerves that are injured, so they can heal and regenerate.
  • INFLAMMATION. Like any tissue in the body, nerves can become inflamed and therefore damaged. Individual nerves (or neurons) have a lining, or sheath (called myelin sheath) around them which also can get very inflamed and cause persistent pain. It is important to reduce myelin sheath and nerve inflammation as quickly as possible to allow the nerve to heal.
  • SEVERING. Depending on whether a nerve is partial or fully cut, signal transmission is disrupted. This can lead to a variety of symptoms of varying degrees.
  • TRACTION. When a nerve is pulled or tugged forcefully, its ability to fire is compromised. This may occur from falls or direct blows into parts of the body where the nerves run.
  • METABOLIC IMBALANCE. Metabolic disturbances such as diabetes, thyroid disease and an abnormal lipid profile can cause injury to nerves, with the severity of the injury depending on the degree of imbalance.
  • VITAMIN AND MINERAL DEFICIENCIES. If left untreated, deficiencies in Vitamin B1, B12, along with Magnesium and Calcium can cause nerve disturbance.
  • DRUGS, Toxins and Medications. Some substances and medications can cause temporary or even permanent nerve damage. It is important to check your medication with your doctor for any potential side effects.
peripheral nerves

All the forms of nerve injury described above can change the firing pattern of nerves, increasing pain and producing weakness. However, nerve entrapments make up the vast majority of PNIs. We will discuss Peripheral Nerve Entrapment in more detail.

“NO MATTER THE MECHANISM OR SEVERITY OF INJURY, WITH THE RIGHT REHABILITATION AND TREATMENT, PNIs HAVE A REMARKABLE ABILITY TO REGENERATE AND RECOVER”

How do peripheral nerves become trapped?

Peripheral Nerves can become trapped anywhere from the point they leave the spinal cord, to the point they reach muscle and skin. Common mechanisms for nerve entrapment are summarised in the table below.

CAUSE OF PERIPHERAL NERVE ENTRAPMENTEXAMPLES
Prolonged compression on a nerveSleeping on arm (dead arm)
Sitting down too long
Tight clothing and footwear
Masses compressing on a nerveSpinal Disc herniation (aka disc bulge)
Cysts
Tumours
Fluid collections (e.g., haematoma)
As the nerve passes through other structuresInternal organ
Foramen (bone tunnels)
Soft tissue tunnels (e.g., carpal, cubital, tarsal)
As the nerve passes through muscle groupsCore and trunk
Head and neck
Pelvic floor
Upper and lower limb
As the nerve passes around a structureJoints
Bone

What are the symptoms of peripheral nerve injury?

Given their passage, peripheral nerves can become injured anywhere from the spinal cord to the more peripheral parts of the body (muscles and skin). Sensory and motor nerves are much more likely to get injured along their course than autonomic nerves (which tend to supply internal organs like the heart, gut). Sensory and motor nerve injury can in turn lead to sensory and motor symptoms.

  • SENSORY SYMPTOMS. Peripheral nerves that transmit information about sensations (such as touch and feel) follow set patterns of distribution, called Dermatomes. Depending on which part of the spinal cord the nerve exits, dermatomes can be divided into segments, cervical, thoracic, lumbar and sacral. Within each segment there are different numbered levels (see diagram). It is therefore sometimes possible to predict which nerves have been injured by where sensory symptoms are felt. Sensory symptoms may include.
    • Pain. Pain symptoms can range from sharp to dull, persistent to intermittent, and remain in one location or radiate to other parts of the body.
    • Numbness. This may present as a partial or complete loss of feeling or touch sensation.
    • Paraesthesia. This essentially means “pins and needles” and can be associated with numbness.
    • Loss of Proprioception. As well as sensations, sensory nerves also contain information around body part movements and balance. For example, injury to certain nerves in the leg and make the ankle feel less stable.
  • MOTOR SYMPTOMS. Peripheral nerves that transmit motor (or movement) information also travel in set patterns of distribution, called Myotomes. Myotomes, closely correlate with dermatomes. It is therefore also possible to determine which nerve (or nerves) have been injured depending on where symptoms are located. Motor symptoms may include:
    • Weakness. The most common motor sign is a reduction in power of a single or group of muscles. With acute PNIs (e.g., nerve trauma), weakness can come on quite quickly. With more chronic nerve injuries (e.g., slow nerve entrapment or compressions), weakness may be very subtle and take weeks or months to become apparent.
    • Muscle wasting. The muscles that are supplied by an injured nerve may become smaller in size or completely wasted over time. Examples of this may include reduced calf muscle bulk in sciatica or hand muscle wasting carpal tunnel. Wasted muscles are usually lacking in strength and power but usually can be rebuilt.
    • Hypotonia. The tone (ability to contract) of a muscle can also be affected with motor nerve injury. This may leave muscles flaccid, floppy and unable to produce forceful contraction.
    • Slow reflexes. Motor nerves are also responsible for giving muscles and tendons their reflex responses. Reflexes can become slower and more sluggish after nerve injury. This can be tested in clinic with a tendon hammer.
peripheral nerves

How do we diagnose peripheral nerve injuries (PNIs)?

Most PNIs are diagnosed clinically, after discussing your symptoms and examining thoroughly to look and test for the signs mentioned above. There are different ways of further investigating PNIs. They can be divided into investigations that (1) look at the nerve and its surrounding structures (2) test the conduction and speed of the nerves. Both these investigations may help to confirm the diagnosis and plan the rehabilitation.

  1. Investigations that visualise the nerve and its surrounding structures mainly include MRI and ultrasound scans. These can identify anything that may be compressing the nerve or surrounding inflammation. It may be possible to tell if the injured nerve is thickened or swollen.
  2. Investigations that test how well a nerve is conducting include Nerve Conduction and EMG studies.

How do we treat PNIs?

The first step to treating a PNI is to rectify the cause the injury, thus restoring normal function to the nerve. The table below describes some treatment options.

NERVE INJURY MECHANISMTREATMENT RATIONAL
Nerve EntrapmentRectifying the cause of entrapment through rehabilitation, injection therapy or surgery
Nerve InflammationReducing inflammation around the nerve through natural healing, anti-inflammatory medication, injection or surgery
Severing injuryAllowing the ends of the severed nerve to heal naturally or through surgery
Traction injuryEfforts should be made to ensure a further traction injury does not happen
Metabolic imbalanceCorrecting metabolic disturbances through diet, exercise and medication/supplementation if necessary
Vitamin and Mineral DeficienciesCorrecting vitamin and mineral deficiencies through diet, exercise and medication/supplementation if necessary
Drugs, Toxins and MedicationsRemoving any harmful substances that may be contributing to PNI

The role of rehabilitation and therapy in the treatment of PNIs

“REHABILITATION AND THERAPY SIGNIFICANTLY INCREASE THE CHANCE OF RECOVERY AFTER A PNI, WHATEVER THE CAUSE”

A comprehensive and well considered rehabilitation programme is key when treating PNI. Rehabilitation can be targeted to improve sensory and/or motor symptoms. Therapy and exercise can also significantly improve nerve entrapment, by lengthening the nerve and releasing structures (e.g., muscle tension, disc herniations, joints). Different forms of therapy for PNI may include:

  • Physiotherapy
  • Strength and conditioning
  • Hydrotherapy
  • Muscle stimulators and tens (transcutaneous electric nerve stimulation)
  • Desensitisation programmes

IT IS IMPORTANT TO DISCUSS ANY POTENTIAL SIGNS AND SYMPTOMS OF PERIPHERAL NERVE INJURY WITH YOUR DOCTOR TO GET A CLEAR DIAGNOSIS AND TREATMENT PLAN.

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    Orla Mulligan
    Administration and Social Media Manager
    Administration, LBSM

    Orla Mulligan is the administration and social media manager for LBSM. She has a strong background in sport having herself played netball at an elite standard for the U21s Northern Ireland team in the European Championships as well as the U21s competition for Saracen Mavericks.

    She understands youth sport pathways having herself played and training in the netball Kent regional pathway. She has a keen interest in most sports and a good understanding of how injury and illness can impact on the mind and body, as well as rehabilitation pathways.

    She looks forward to speaking and assisting LBSM patients and gives her best support to them during their treatment pathway.

    A day in the life of Orla involves communicating with patients via phone and email, managing and organising clinics, operations and media management.

    Outside of work, Orla is a gym enthusiast, enjoys tennis and still finds the time for an occasional game of netball.

    Maddie Tait
    BSc, MSc
    Associate, LBSM
    Musculoskeletal and Sports Podiatrist

    Maddie treats and manages complex foot and ankle injuries in London and Surrey.

    She is particularly interested in helping her patients improve their quality of life and achieve their personal goals, working closely with Foot and Ankle Consultants, Sports Medicine Doctors and Physiotherapists.

    Maddie has a sporting background herself having previously represented England in Hockey. She understands the demands of elite sport and the importance of physical and mental health. In her spare time, Maddie continues to enjoy an active lifestyle by running, cycling and attending a Pilates class.

    Having graduated from University of Brighton with a MSc (hons) in Podiatry, Maddie focused her career in Podiatric Sports Injuries and Biomechanics. Previously she completed a BSc (hons) in Sport Science at Loughborough University.

    A day in the life of Maddie involves consulting patients in clinic, performing gait and biomechanical assessments, measuring and fitting orthotics and braces. She also regularly teaches and presents at sports medicine and podiatry conferences.

    Outside of work, Maddie still finds time to play hockey and enjoys running and skiing.

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    MBBS, PhD, FRCS
    Consultant Partner, LBSM
    Consultant in Vascular Surgery

    Mr Prakash Saha is a Consultant Vascular Surgeon at LBSM. He takes pride in providing the best possible results for his patients by using the most appropriate non-surgical and surgical methods based on clinical evidence, patient results and satisfaction.

    He treats fit and active people suffering with a range of cardiovascular issues, from painful leg swelling associated with exercise to venous insufficiency, post-thrombotic syndrome and leg ulcers. He also treats people with arterial system problems including poor circulation, compression syndromes and aneurysms. He carries out both endovascular and open aortic repair and has some of the best outcomes in the country.

    Mr Saha studied medicine at the United Medical & Dental Schools at Guy’s and St. Thomas’ Hospitals before completing his higher surgical training in London and the South East. During this time, he was awarded the prestigious NIHR Clinical Lectureship in Vascular Surgery at St. Thomas’ Hospital, giving him comprehensive training in open and endovascular techniques for treating arterial and venous disease. Prakash completed his aortic surgery training at the St. George’s Vascular Institute before carrying out a specialist fellowship at the Royal Prince Alfred Hospital, Sydney.

    Mr Saha regularly lectures and runs workshops across the globe on the latest surgical techniques to treat vascular disease. He has also been awarded a number of research grants from the Royal College of Surgeons, the Circulation Foundation, the Wellcome Trust, the Academy of Medical Sciences, and the British Heart Foundation, which has led to over 80 publications and the development of innovative technologies to help treat patients. For this work, Prakash has received a number of prizes, including the Venous Forum prize from the Vascular Society of Great Britain and Ireland, an International Young Investigator Award, and an Early Career Investigator Award from the American Heart Association.

    A day in the life of Mr Saha involves seeing patients in clinic, operating in surgical theatre or lecturing at his university. He also regularly teaches and presents at vascular and sports medicine conferences.

    Mr Saha is an avid cyclist and tennis player (although yet to get a set of Dr Seth!). Outside of work, he spends time with his family who consists of 3 children and enjoys travelling.

    Dr Gajan Rajeswaran
    MBBS, FRCR
    Consultant Partner, LBSM
    Consultant in Sports and Musculoskeletal Radiology

    Dr Gajan Rajeswaran is a Consultant Musculoskeletal Radiologist at LBSM, with an extensive background of working in elite sport. He is one of the most recognised radiologists in the sports medicine field. He provides top level imaging and medical diagnostic services for patients and athletes.

    Dr Gajan Rajeswaran completed his undergraduate medical training at Imperial College London and his radiology training at Chelsea & Westminster Hospital. He has obtained two post-CCT fellowships in musculoskeletal imaging. He was appointed as a consultant at Chelsea & Westminster Hospital in 2011.

    He has a passion for all sports having worked as a radiologist at the Glasgow Commonwealth Games and London World Athletic Championships and continues to support The Championships, Wimbledon. He also continues to work with a number of Premier League and Championship Football Clubs, Premier League Rugby Clubs, England Sevens Rugby, British Athletics and the Lawn Tennis Association.

    A day in the life of Dr Rajeswaran involves giving his expert opinion on investigations such as MRI and CT scans, x-rays and ultrasound. He also performs injection lists under ultrasound, CT and X-ray including spinal injections. He also regularly teaches and presents at sports medicine conferences.

    Dr Gajan Rajeswaran is an avid football fan and life-long fan of Tottenham Hotspur (for which he offers no apologies!). Outside of work, he spends time with his family and has a keen passion for photography.

    Dr Ajai Seth
    MBBS, BSc, MSc, MRCS, MRCGP, FFSEM
    Medical Director, LBSM
    Consultant in Sport and Exercise Medicine

    Dr Ajai Seth is a Sport and Exercise Medicine Physician. He has dedicated his career to helping people with sport and exercise related injury and illness. He consults and treats everyone from the elite athlete to the weekend warrior.

    Dr Ajai Seth is part of the British Tennis Sports Physician team at the LTA and has also provided cover to elite athletes at Wimbledon Tennis, European Tour Golf, Premier League Football, British Athletics, and the Men’s England Football academies as part of the FA.

    He also prides himself for working in disability sport and is currently the Chief Medical Officer for Team GB Wheelchair Tennis which has taken him to the Olympics and Paralympics.

    Dr Ajai Seth is dedicated to education, training and research and is a Senior Lecturer in Sports Medicine at King’s College London where he lectures in all aspects of Sports Medicine and Science.

    He also has a passion for travel and Expedition Medicine, which has seen him accompany medical, scientific and charity expeditions all around the world. He also has vast experience in treating musculoskeletal injuries from children and adolescents to veteran exercisers, both male and female.

    Dr Seth also has positions in leading Sport Medicine organisations, including the non-executive board for the UK’s largest Sports Medicine charity, BASEM and Past President for the Royal Society of Medicine. 

    A day in the working life of Dr Seth involves consulting his patients in clinic, performing diagnostics and ultrasound guided injections. He also regularly lectures and tutors students and presents at sports medicine conferences internationally. He also spends part of the working week at the National Tennis Centre, LTA, supporting British Tennis players.

    Outside of work, Dr Seth enjoys playing club tennis, triathlon, golf, running and skiing (but will give any sport a go!). He enjoys keeping fit and active and good quality family time with his wife and three children.