We experienced a patient with a medial CF following RND in 2010. We performed a total of 25 RND procedures from 2008 to 2019, and the present patient represented the only case of a CF after RND.
However, similar cases of CF after neck dissection have been reported by other researchers [4, 5, 7,8,9,10,11,12,13,14,15], who advocated various hypotheses regarding their causes.
Strauss et al.  and others [4, 7, 8, 14] considered that CF after neck dissection was a result of weakening of the bone and blood supply caused by neck dissection and/or radiotherapy. However, the current patient did not receive radiation therapy. Other reports of medial CF after neck dissection indicated that neck dissection alone might cause such fractures, with or without postoperative radiotherapy [11, 14].
Regarding the possible association between CF after neck dissection and bone destruction, Shodo et al.  reported a case of CF after neck dissection and postoperative radiotherapy followed by osteomyelitis with bone destruction. They suggested that osteomyelitis and abscess formation with bone destruction caused by risk factors such as radiotherapy, tracheostomy, and adjacent infection might complicate the fracture findings, such as bone destruction in clavicle stress fractures after neck dissection . In both the current and Shodo et al.’s case, the fracture was accompanied by bone destruction; however, our case was not associated with infection.
Fujimoto et al.’s  study was also relevant to the association between CF after neck dissection and bone destruction. They assessed the CT images of nine cases of CF following neck dissection and suggested that proximal CF consistently showed an extraosseous soft-tissue mass formation without bone destruction on CT . In our case, the patient had no subjective symptoms related to the fracture, despite the formation of an extraosseous soft-tissue mass, as in Fujimoto et al.’s cases. However, the fracture in the present case was accompanied by bone destruction, which was absent in Fujimoto et al.’s cases.
The pathogenesis of bone destruction in CF after neck dissection might be associated with multiple factors, and the cause for the bone destruction in the current patient has not yet been identified. However, comparing the present and previous cases of CF, our case suggests that postoperative chemotherapy after RND might contribute to bone destruction in CF, even in the absence of radiotherapy [8, 16] and infection  of the clavicle. The influence of chemotherapy on the occurrence of CF after neck dissection remains unknown. One study reported a possible effect of chemotherapy on bone , while some cases of CF following neck dissection have been reported in patients without chemotherapy [7,8,9,10], and others have been noted in cases with chemotherapy [8, 9]. Further studies are therefore needed to elucidate the influence of chemotherapy in the pathogenesis of CF after neck dissection.
In the present patient, the CF was first discovered during a follow-up imaging examination, and the CF status during the 6 months from RND to its first discovery remains unknown. We are therefore unable to explain the interaction between the fracture and the bone destruction. Future cases should thus consider the mechanism of bone destruction in CF after neck dissection.
The current case shows that CF after RND may be accompanied by bone destruction, even if the fracture is not associated with infection. Moreover, in our case, bone destruction of the CF might have progressed because the discovery of the fracture was delayed. This case highlights the need to recognize CF as one of the adverse events after neck dissection , and to ensure that the condition is promptly detected and treated. Regular follow-up imaging examinations, including CT, will aid the rapid discovery of CF after neck dissection for head and neck cancer [8, 13, 14].
CF is a rare complication after treatment for head and neck cancer but can be caused by neck dissection. Regular imaging examinations, including the clavicular region, should, therefore, be carried out before and after surgery to ensure the prompt detection of CF.