Baxter’s nerve entrapment, also known as inferior calcaneal nerve entrapment or Baxter’s neuropathy is a relatively uncommon condition that can result in pain and discomfort in the heel and ankle region. It occurs when the inferior calcaneal nerve, which runs along the bottom of the foot, becomes compressed or impinged, leading to symptoms such as tingling, numbness, or shooting pains. In this blog, we will explore the history of Baxter’s nerve entrapment, its causal factors and symptoms, and the various treatment options available for those affected by this condition.
The first recorded instance of Baxter’s nerve entrapment was identified by Dr David Baxter in 1984, who described the condition in a series of case studies. Since then, the condition has been recognised by the medical community, albeit as a somewhat rare disorder. Baxter’s nerve entrapment typically occurs in individuals who have experienced injury or trauma to the foot or ankle, such as from repetitive strain or direct impact. It can also be caused by the presence of anatomical variations, such as a cyst or bone spur, or by wearing tight-fitting shoes. Some speculate that it can also be caused by chronic plantar fasciitis.
The presentation of Baxter’s nerve entrapment can vary depending on the severity of the condition and the individual patient. Symptoms may include a tingling or burning sensation in the heel area, pain in the foot or ankle, or numbness or weakness in the affected extremity. In severe cases, the sufferer can’t fan out the 5th toe away from the 4th. Symptoms may worsen with activity or at night when lying down. In some cases, the condition may be mistaken for plantar fasciitis, Achilles tendonitis, or tarsal tunnel syndrome, which can make diagnosis challenging. Diagnosis can be hampered by the fact that nerve conduction studies (a test that measures how well nerves function) are often inconclusive for Baxter’s nerve entrapment. A key distinguishing factor that separates plantar fasciitis from Baxter’s nerve entrapment is the nature of the discomfort. Typically, the discomfort from plantar fasciitis is experienced during the first few steps in the morning and when weight-bearing after rest. The discomfort from plantar fasciitis will often improve after the initial discomfort. By contrast, the discomfort from Baxter’s nerve entrapment will just often build throughout the day and can often generate pain at rest which plantar fasciitis doesn’t.
There are several treatments available for managing Baxter’s nerve entrapment, including conservative and surgical options. Conservative treatments may include the use of orthotics or foot pads to provide support, physiotherapy to strengthen the foot and ankle muscles, and non-steroidal anti-inflammatory medications to reduce inflammation and pain. In more severe cases, surgery may be necessary to release the impingement on the nerve and alleviate the symptoms.
In our opinion, non-invasive focused shockwave treatment (not to be confused with radial shockwave) is the best treatment option.
Focused shockwave treatment (FSWT) is a therapeutic modality that has gained considerable attention in recent years due to its potential for treating various musculoskeletal conditions, including nerve pathology such as nerve entrapments, this is because focused shockwave treatment can exert powerful positive physiological effects on Baxter’s nerve.
The Physiological Effects of Focused Shockwave Treatment include:
- Stimulation of Healing Processes:
FSWT has been shown to stimulate angiogenesis, which is the formation of new blood vessels. This effect is attributed to the release of various growth factors, such as vascular endothelial growth factor (VEGF), which promotes the growth and regeneration of blood vessels around the damaged nerves (Wang et al., 2020). Improved blood circulation facilitates the delivery of oxygen and nutrients to the affected nerves, aiding in their healing and regeneration. - Enhanced Nerve Conduction:
Another physiological effect of FSWT is the potential enhancement of nerve conduction velocity (NCV) in nerve entrapments. NCV refers to the speed at which electrical impulses travel along a nerve fibre. Studies have reported an increase in nerve conduction velocity after FSWT, indicating improved neural transmission along the affected nerve pathways (de Almeida et al., 2019). This effect may contribute to the alleviation of symptoms associated with nerve entrapments, such as pain, numbness, and tingling sensations. - Modulation of Pain Pathways:
FSWT has demonstrated analgesic effects, potentially reducing pain associated with nerve pathology. It has been suggested that shockwave therapy could stimulate the release of endorphins, which are natural pain-relieving substances produced by the body (Wang et al., 2020). Additionally, FSWT may disrupt pain signalling pathways and activate nerve fibres responsible for inhibiting pain transmission (Rompe et al., 2018). These combined mechanisms can contribute to a reduction in pain intensity and an overall improvement in nerve-related symptoms. - Reduction of Inflammation:
In nerve entrapments, inflammation plays a crucial role in exacerbating symptoms and delaying healing. FSWT has been found to exhibit anti-inflammatory effects by reducing the synthesis of pro-inflammatory cytokines, such as tumour necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) (de Almeida et al., 2019). Suppression of these inflammatory mediators helps to minimize tissue oedema and reduce the local inflammatory response, thus promoting a favourable environment for nerve recovery.
Conclusion:
Focused shockwave treatment demonstrates several physiological effects that can benefit nerve entrapments such as Baxter’s nerve entrapment These effects include the stimulation of healing processes, enhanced nerve conduction, modulation of pain pathways, and reduction of inflammation. By harnessing these mechanisms, FSWT holds promise as a non-invasive and effective treatment option for individuals suffering from nerve entrapments. Practically speaking focused shockwave is very well tolerated by patients with many only requiring one or two fifteen-minute sessions. Furthermore, complications from focused Shockwaves are practically non-existent.
References:
- Baxter DE. Release of the nerve to the abductor digiti minimi. Foot Ankle. 1984;5(6):300-302.
- Samim M, Smith CC, Grodofsky S, Mehta SP, Wong AKO. Ultrasound-Guided Nerve Block of Baxter’s Nerve for Treatment of Inferior Heel Pain: A Case Series. Foot Ankle Spec. 2021 Jun;14(3):229-234. doi: 10.1177/1938640020926617. Epub 2020 Jun 2. PMID: 32486914.