Trismus—An important issue in pain and palliative care

In this issue of Scandinavian Journal of Pain a multidisciplinary group of authors presents an interesting systematic review on trismus in head and neck cancer including an illustrative case report [1]. Trismus is a motor disturbance of the trigeminal nerve, especially spasm of the masticatory muscles, with difficulty in opening of the mouth (lockjaw),^[1] and it may be caused by a number of mechanisms. Different time trajectories are evident, ranging from trismus caused by rapid injection of ultra-fast-acting opioids, malignant hyperthermia, head trauma, severe ENT-infections, tetanus, temporomandibular dysfunction and neurological diseases. Cancer related trismus is a feared complication due to recurrence of the cancer or as an adverse effect of the oncological treatment. A PubMed search January 2010 rendered on “trismus cancer” 346 cites including 40 reviews. The newest review, published 2009, included studies from 1997 to 2007 [2], while Wranic et al. cover the literature up to June 2009.

Trismus is an important topic from a pain and palliative care aspect. The present authors correctly point out that several influential international textbooks on pain and palliative medicine do not mention this complication. This has, however, been corrected for the recently published fourth edition of Oxford Textbook of Palliative Medicine (the definition of trismus is here “limited mouth closing” [3]).

In Scandinavia the standardized incidence of head and neck cancer is approximately 90–100 new cases per year per million inhabitants, with a ratio between males and females of 2–3:1 [4, 5]. The major sites of head and neck cancer are the oral cavity, the oropharynx, the larynx, the hypopharynx and the nasopharynx [2]. The management depends on site and stage of the cancer, but generally consists of surgery, radiotherapy and chemotherapy or a combination of these methods.^[2] Although tissue preservation has a high priority in advanced cancer, oncological management and in particular radiotherapy, can irreversibly injure oral mucosa, vasculature, muscle, and bone [6]. This may, in addition to trismus, result in xerostomia, soft tissue necrosis, and osteoradionecrosis. In many patients trismus may severely compromise speech, eating, swallowing and breathing and lead to pain, malnutrition, loss of weight, aspiration and a profound reduction in quality of life [2].

What is the best available evidence for prevention and management of trismus in head and neck cancer? Unfortunately very few controlled, randomized trials are available. The technique of radiotherapy in regard to the extent of the radiation field and the number of fractions used may attenuate fibrosis of the soft tissues [1]. There seems to be moderate evidence for the efficacy of physiotherapeutic interventions including stretching and use of prosthetic aids [2, 7, 1]. Pharmacological controlled, randomized trials are very few and those available are low powered [7]. A number of papers have propagated for a coordinated multidisciplinary approach in research and in treatment of the head and neck cancer patient with trismus [8, 2, 1], but the evidence is annoyingly scarce.

It could be interesting to attend the problem of trismus and other cancer related symptoms from a more holistic perspective. The illustration shows hypothetically some of the variables and the vicious circles that are initiated by the cancer and its treatment [9, 10, 11]. Tissue injury leads to pain and impaired physical functioning. Pain-induced sensitization (“wind-up”, long-term potentiation) contains early and late components, which lead to more pain and increased reflex-induced physiological malfunctioning. The physiological deconditioning may even lead to more pain [12]. Pain and sensitization lead to impaired psychosocial functioning (sleep deprivation, fatigue, isolation, catastrophizing behaviour, anxiety and depression). All of these variables interact, but pain is a key factor. It is evident why the pain, starting with acute pain, slowly may become intensified and develop into chronic pain and severely may affect the individual physiologically and psychosocially. The illustration can easily be adapted to head and neck cancer and explain the multifaceted symptomatology seen in trismus. Originally the model was used to illustrate the transition from acute to chronic post-surgical pain [9, 10, 11].

A rational treatment plan should contain minimal invasive and tissue preserving therapeutic methods (1), aggressive multimodal analgesic therapy (2), antihyperalgesic agents [gabapentinoids, antidepressants, NMDA-blocking agents, α2-agonists (3)], rehabilitation with special emphasis on nutrition and exercise issues (4) and psychosocial support ranging from cognitive behavioural therapy to management of anxiety and depression (5).

This set up requires a multidisciplinary collaborative effort from anesthesiologists, nurse specialists, nutritionists, oncologists, palliative specialists, pain-specialists, physiotherapists, psychologist, radiotherapists, speech therapists and ENT-surgeons. Standardized care plans, protocols and clinical pathways are critical for successful implementation, as it has been in fast-track surgery [13, 14]. The improvements by these programmes in perioperative care during the last decade could hopefully be translated into the general management principles in head and neck cancer. The sooner the better—for the patient and the health care system.