Anatomy and physiology

CTS and SLAC are two distinct conditions that affect different anatomical structures in the wrist and hand. CTS involves compression of the median nerve within the carpal tunnel, while SLAC involves degeneration and shifting of the scaphoid and lunate bones in the wrist. The carpal tunnel is a narrow passageway located in the wrist that is formed by the carpal bones and the transverse carpal ligament. Within this tunnel, the median nerve, along with nine flexor tendons, passes from the forearm into the hand. In CTS, the median nerve becomes compressed due to swelling or thickening of the surrounding tissues, leading to pain, numbness, and tingling in the hand and wrist (thumb, index, middle, and ring fingers). This is because the median nerve provides sensory and motor function to these fingers, as well as to the muscles that control movement of the thumb. The compression of the median nerve can also affect blood flow to the hand, leading to weakness and muscle wasting over time. In contrast, SLAC involves the scaphoid and lunate bones, which are located in the proximal row of the carpal bones. Herein, the ligaments that hold the scaphoid and lunate bones together become weakened or damaged, causing the bones to shift out of position. In SLAC, this can lead to pain, swelling, and reduced mobility in the wrist (affected joint), as well as an increased risk of arthritis. The shifting of the scaphoid and lunate bones can also affect the movement of the adjacent joints in the wrist, as well as the alignment of the bones in the hand and forearm. Over time, this can lead to the development of arthritis in the wrist joint, which can further limit mobility and cause pain and discomfort. The anatomical and physiological changes associated with both, CTS and SLAC, can have a significant impact on the function and comfort, and beyond, of the affected individual.

Definition, etiology, and classification

SLAC, as mentioned above, is a condition that results from the degeneration of the wrist joint. This degeneration can cause the scaphoid and lunate bones in the wrist to collapse and become unstable, leading to chronic pain, stiffness, and limited mobility in the wrist. CTS, then again, is caused by the compression of the median nerve as it travels through the carpal tunnel in the wrist. This compression can be caused by repetitive motions, awkward postures, and other factors that put pressure on the median nerve. CTS can be classified into mild, moderate, or severe categories based on the severity of symptoms. Likewise, there are different classes of SLAC, which are based on the progression of the disease.

• Stage I SLAC: In this stage, there is evidence of scapholunate ligament injury, but the space between the scaphoid and lunate bones is still preserved.

• Stage II SLAC: In this stage, the space between the scaphoid and lunate bones is reduced, and the scaphoid bone may have started to collapse.

• Stage III SLAC: In this stage, the scaphoid bone has collapsed completely, and the lunate bone has shifted forward.

• Stage IV SLAC: In this stage, the bones in the wrist have become arthritic, and there is significant degeneration in the wrist joint.

Diagnosis and treatment strategies

It is important for healthcare providers to accurately classify CTS and the stage of SLAC in order to determine the appropriate treatment plan for their patients. The diagnosis of SLAC and CTS involves a physical examination, medical history, and diagnostic tests such as X-rays, MRI, and electromyography (nerve conduction study). Treatment options for these conditions aim to alleviate symptoms, restore normal anatomy and physiology, and prevent further damage or degeneration of the affected tissues. Henceforth, treatment strategies may include non-surgical options such as rest, physical therapy, and the use of wrist splints or braces (for immobilization). In more severe cases, surgery may be necessary to relieve pressure on the median nerve and stabilize the wrist joint. Indeed, wrist surgery, such as wrist fusion, is often necessary for SLAC stage II and III to prevent further damage to the wrist joint. SLAC stage IV is associated with advanced arthritis and may require more extensive surgical intervention, such as total wrist fusion or wrist replacement. Therefore, a personalized treatment plan should be developed based on the specific case, needs and goals of each individual patient.

Emerging therapeutic trends

Emerging treatment options for CTS and SLAC are being investigated to provide alternative options to traditional treatment modalities. One such treatment option is regenerative medicine, which uses stem cells or growth factors to regenerate damaged tissues in the wrist. A recent Khan et al. study found that autologous adipose-derived mesenchymal stem cell injection was effective in reducing wrist pain and improving wrist function in patients with CTS, with no adverse effects observed. Additionally, a separate study by Zhang et al. found that bone marrow-derived mesenchymal stem cell injection was effective in reducing pain and disability in patients with SLAC. Another emerging treatment option for CTS and SLAC is arthroscopy, a minimally invasive surgical technique that allows surgeons to view and treat the inside of the wrist joint using small incisions. A study reported by Zhou et al. found that arthroscopic-assisted reduction of intra-articular distal radius fractures in patients with SLAC was an effective treatment option with a low complication rate. Furthermore, Altinel et al. found that arthroscopic decompression of the carpal tunnel resulted in significant improvement in grip strength and pain relief in patients with CTS. Further, joint distraction is another treatment option that has been explored for CTS and SLAC. It involves pulling apart the bones in the wrist joint using external fixators to improve blood flow and promote healing. According to Van Doesburg and group, joint distraction was an effective treatment option for CTS, with patients experiencing significant improvement in wrist function and symptom relief. Recently, Deshmukh et al. found that joint distraction combined with autologous bone marrow aspirate concentrate was effective in treating SLAC, with patients reporting significant improvement in wrist pain and function. It is worth mentioning however that while these emerging treatment options show promise, further research is needed to determine their efficacy and safety. It is important to note that such therapy options may not be appropriate for all patients and should be considered on a case-by-case basis.

Some recent developments in the treatment of CTS include the use of minimally invasive techniques such as endoscopic carpal tunnel release and ultrasound-guided techniques. Additionally, researchers are exploring the use of new technologies such as PRP and stem cell therapy to aid in the healing and regeneration of damaged nerves. As for SLAC, recent surgical advancements include the use of arthroscopic techniques for joint debridement and reconstruction, as well as the use of various types of implants and prostheses to help stabilize and support the affected joint. Additionally, researchers are investigating the use of regenerative medicine techniques, such as PRP and stem cell therapy, to help promote tissue repair and regeneration in the wrist joint.

Implications for dentists and maxillofacial surgeons: Dentists and maxilla-facial surgeons are at increased risk of developing CTS and SLAC due to the repetitive motions and awkward postures required in their work, and/or due to trauma. These conditions can lead to chronic pain, disability, and a decreased ability to perform their jobs effectively. It is important for these professionals to take steps to protect themselves from CTS and SLAC by practicing good ergonomics, taking breaks to rest and stretch their hands and wrists, and using tools and equipment that reduce the strain on their hands [5]. Early diagnosis and treatment of CTS and SLAC is also deemed crucial to help prevent further damage and manage symptoms effectively.

Conclusions

In conclusion, SLAC and CTS can have a significant impact on the work and quality of life of dentists and surgeons. As these professionals rely heavily on their hands and wrists to perform intricate and precise procedures, any impairment to these areas can greatly affect their ability to perform their job effectively, safely, and comfortably. For a dentist with SLAC and/or CTS, the condition can make it difficult to hold and manipulate dental instruments, leading to decreased precision and control. It can also cause discomfort and pain during prolonged procedures, as well as limit the number of procedures that can be performed in a single day. Similarly, for a surgeon with SLAC and/or CTS, the condition can affect their ability to hold and manipulate surgical instruments, leading to decreased precision and control during procedures. It can also cause pain and discomfort during prolonged surgeries and limit the number of surgeries that can be performed in a single day. In both cases, the condition can have a negative impact on the efficacy and quality of work performed, as well as the overall comfort and quality of life (QoL) of the dentist or surgeon. Therefore, it is important for these professionals to receive prompt and appropriate treatment for their condition in order to minimize its impact on their work and QoL. Henceforth, both, dentists, and surgeons, amongst others, must also be aware of the potential risks associated with CTS and/or SLAC and take proactive measures to appropriately protect themselves from developing these serious conditions. By doing so, they can ensure that they are able to provide the highest level of care to their patients while maintaining their own health, well-being and QoL.

Declarations

Conflict of interest: None.

Funding and acknowledgments: This work was supported by operating grants provided to the HAiDAR R&D&I LAB/BioMAT’X (Laboratorio de Biomateriales, Farmacéuticos y Bioingeniería de Tejidos Cráneo Máxilo-Facial), member of CiiB (Centro de Investigación e Innovación Biomédica), Faculties of Medicine and Dentistry, Universidad de los Andes, Santiago de Chile, through the ANID-NAM (Agencia Nacional de Investigación y Desarrollo, Chile and National Academy of Medicine, NIH, USA) Grant código # NAM21I0022 (2020-2022), CORFO Crea y Valida I+D+i Grant código # 21CVC2-183649 (2021-2023), CORFO Crea y Valida — Proyecto de I+D+i Colaborativo - Reactívate” Grant código # 22CVC2-218196 (2022-2024), and FONDEF Concurso IDEA de I+D, ANID, Grant código # ID22I10215 (2022-2024). The author requests to disclose that this piece was inspired due to/ following a personal experience.

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