Application of Botox in The Management Of Musculoskelketal Pain

Botulinum Toxin happens to be one of the most potent neurotoxins comprising of a 50 kDa light chain and a 100kDa heavy chain, which are linked by a disulphide bond. 7 serotypes ranging from A to G have been identified.  It exists in seven serotypes, A through G. It has been seen the Botulinum Toxin is responsible for  interference with the expression  of various neuropeptides such as Substance P and calcitonin gene- related protein (CGRP), which are key mediators of neurogenic inflammation.[1] Botulinum toxin A(BoNT/A) injections have been seen to reduce paw edema in formalin treated rat cadavers, lower the tissue glutamate release and obtund spinal cord excitability. In all, it has been recognised that Botulinum is an inhibitor of cytokines, neuropeptides and other inflammatory mediators. Lot of clinical studies support the proposed anti- nociceptive mechanism of action o0f Botulinum Toxin.

APPLICATIONS– The neuromuscular blockade brought about by BOTOX has been seen to give good relief of pain and improvement of function in patients suffering with painful and chronic musculoskeletal ailments.

  • OSTEOARTHRITIS– BOTOX is being increasingly used in the non invasive management of arthritis of the knee, hip, shoulder and other joints as well. Significant improvement in pain scores and quality of life was seen in  a lot of patients. Moore and colleagues saw marked improvement in patients of knee arthritis, injected with BOTOX.
  • PLANTAR FASCITIS– One of the commonest foot and ankle condition encountered in the society, BoNT injections are helpful in resistant cases( failure of physical therapy and steroid injections). Significant improvement of pain and the near absence of side effects has made it popular amongst the Musculoskeletal practitioners today.
  • TEMPEROMANDIBULAR JOINT PAIN– Pain over the temperomandibular region  which is secondary to overactivity of the masticatory muscles responds well to intramuscular BOTOX injections. Injections  are usually given via an oral route. Studies have shown that the usual preferred dose is 50 units into the masseter and 25 units injected into the temporalis. Studies have reported upto 80% of patients experiencing lasting  pain relief upto  10-12 months.
  • TENNIS ELBOW/ LATERAL EPICONDYLITIS: Probably the most common cause of tennis elbow, studies have reported reduced pain and improvement in daily activities after BoNT-A injection. Care has to be taken to monitor the dosage as reductions in finger movement and grip strength have occurred due to the  motor effects of BoNT-A, although the motor block is only temporary in nature.
  • CHRONIC EXERTIONAL COMPARTMENT SYNDROME: A condition resulting in compression symptoms due to increased pressure in an osteofascial muscle compartment,  usually after exercise. Based on limited evidence, BoNT-A injections may be a safe and effective treatment, in some cases avoiding the need for surgery.

Heel that is responsible for heel pain is the retrocalcaneal bursa.

Introduction

The most likely bursa around the heel that is responsible for heel pain is the retrocalcaneal bursa. This pain results when this bursa( sac like structure lined by a thin layer of synovial fluid, functions to reduce friction between surfaces) gets filled up with inflammatory fluid and results in Retrocalcaneal Bursitis. The location of the bursa is between the calcaneum and the anterior surface of the Achilles tendon. There are two bursae in this area.[2] Deep to the Achilles tendon lies the subtendinous or retrocalcaneal bursa. Superficial to the Achilles lies the subcutaneous calcaneal bursa (This bursa lies between posterior surface of the Achilles tendon and the skin). Inflammation of either of these bursae can lead to pain at the posterior heel and ankle region.

Relevant Clinical Anatomy And Pathogenesis

The retrocalcaneal bursa  is housed over the posterio-superior prominence of the heel bone right under the Achilles tendon and it’s lateral expansions. The calcaneum, fibrocartilaginous walls of the retrocalcaneal burial and the insertion of the Achilles tendon form an ‘Enthesis Organ’. Conceptually, at the site of the Achilles tendon insertion, the bursae and the bone are so intimately linked that a small prominence of the calcaneum will greatly increase the chances of mechanical irritation of the bursa.

Etiology

  • Ill-fitting footwear and especially switching to flat shoes after a prolonged period of using high heels can predispose individuals to Retrocalcaneal bursitis.
  • Repetitive micro trauma to the bursa due to excessive loading as is seen athletes who tend to overtrain can be a predisposing factor.
  • Haglund deformity
  • Alteration of the joint axis
  • Gout, rheumatoid arthritis and seronegative spondyloarthropathies

Sign and Symptoms

  • Troubling pain at the back of the hill especially while walking or running uphill.
  • Standing up on toes can aggravate the pain.
  • Tenderness on palpation at the back of heel
  • Swelling often associated with warmth and redness at the back of heel
  • Aggravation of pain with calf loading activities.

Clinical Assessment and Investigations

Careful history and a thorough examination to look for local swelling, tenderness, evaluation of the tendon, detecting any bony prominence as well as locating the area of maximum tenderness with palpation. Tightening of proximal soft tissue, stiffness in joint and any biomechanical abnormalities Should be looked for as these can make one anatomically predisposed to retrocalcaneal bursitis. X rays may show the presence of a bony prominence in the postern-superior aspect of the calcaneum. This is termed as the Haglund deformity . The retrocalcaneal recess often looks normal on weight bearing lateral x rays making their use limited in aiding the diagnosis. Patients may show the absence of normal radiolucency at the posteroinferior corner of the Kager fat pad, (blunting). There may be associated calcaneal erosion seen. Musculoskeletal Ultrasound is a great tool in imaging the bursa, appreciating any bursal thickening, inflammation, health of the adjoining soft tissues and is also mighty helpful in carrying out Interventional Pain Management and Regenerative Procedures for the same. Magnetic resonance imaging (MRI) can demonstrate bursal inflammation but  does not offer much greater  information helping in the diagnosis.

Differential Diagnosis

  • Haglund Deformity
  • Achilles Tendonitis
  • Partial rupture of the Achilles tendon
  • Plantar Fasciitis
  • Posterior Ankle Impingement

Treatment

Physical Therapy

Icing of the heel and posterior part of ankle can be performed several times a day during active inflammation for stretches of 15-20 minutes. Exercises involving the stretching of the Achilles tendon are advised. These can help in relieving the impingement on the subtendinous bursa. Calf stretch
Keeping the back leg straight with the heel placed on the ground one should lean forward against a wall. The front leg has a bend in the knee . To stretch the gastrocnemius complex(calf muscles) and the Achilles tendon, hips have to be pushed towards the wall in a controlled manner. Position is to be held for 10 seconds before relaxing. Excercise should be repeated around 20 times for each foot and this should give the adequate stretch in the calf muscles. Electrical modalities have been tried but are not hugely advocated.

Corticosteroid Injection

Traditionally a lot of people have received blind corticosteroid injections by clinicians for this condition. In our practice, we advocate precise ultrasound  guided injections for really painful bursitis. This makes sure that the  site of the injection is the bursa avoiding steroid infiltration in nearby tissues.

Platelt Rich Plasma & Prolotherapy

For most cases of retrocalcaneal bursitis  encountered at ALLEVIATE,  we follow a Comprehensive Platelet Rich Plasma and  Prolotherapy treatment for the same. Patient usually respond well to treatment in two to three sessions of the same. Though our treatment is coupled with a rigorous multidisciplinary approach focussing on excercise, physical therapy, nutrition and weight management as well.

Surgery

For extremely chronic and resistant cases a Bursectomy might be undertaken.( Rarely done)

What Does Platelet Rich Plasma Contains And How Does It Help In Healing? 

Healing of any injured or damaged tissue is brought about by migration of blood cells towards this are with the help of increased localised blood flow. Platelets reach the injured tissue through this mechanism and are responsible for clotting or coagulation of blood cells or help in minimising blood loss due to the injury. In addition, platelets also release Growth Factors, which are an essential part of the healing process. Platelets are composed of an alpha granule and a dense granule which contain a number of proteins and growth factors. On activation due to injury, the platelets undergo alteration in shape and develop branches to spread over injured tissue to help stop the bleeding in a process called aggregation, followed by the release of growth factors, mainly from the alpha granules.

These growth factors thus give impetus to the healing process and its three stages namely

  • Inflammatory
  • Fibroblastic
  • Maturation

The growth factors derived from the platelets set the inflammatory stage in motion. This is marked by the appearance of monocytes, as they are quick to respond to inflammatory trigger and help in mounting an immune response. Growth factor production is at its highest level immediately following the inflammatory stage. Fibroblasts can be seen to enter the site of injury within 48 hours and become the most abundantly available cells by Day 7. The fibroblasts start depositing collagen (building block of tissues) for many weeks afterwards. Maturation of Collagen is a long phenomenon and may continue for 1-2 years following the initial insult. It is vital to know the stages are a chain reaction with one stage stimulating the next. There would be no collagen deposition by fibroblast if it is not preceded by an inflammatory stage. An insignificant immune response would be insufficient in bringing about regeneration of injured and tissues and make the injured tissue prone for degenerative changes to set in.