Internal fixation surgery effective in improving patients’ quality of life

IVRO and SSRO are common surgical techniques for mandibular setback and are widely used in East Asia to treat patients with mandibular prognathism. Whereas IVRO requires a six-week intermaxillary fixation to achieve bone fixation, SSRO allows for internal fixation using titanium plates and screws, thus enabling immediate jaw function after the surgery.

University of Hong Kong oral and maxillofacial surgery researchers Dr Mike Yiu Yan Leung (left) and Natalie Sui Miu Wong. (Image: University of Hong Kong)

According to the researchers, previous studies showed that IVRO reduces the risk of injury to the inferior alveolar nerve compared with SSRO, which may require a second operation to remove the titanium plates and screws if they are exposed or infected. However, undergoing intermaxillary fixation had not previously been considered from the viewpoint of the patient—a gap that was filled by the present study.

“It is important to understand how different surgical procedures for treating mandibular prognathism affect the patients from their perspective,” commented co-researcher Natalie Sui Miu Wong, who is a doctoral candidate in the Faculty of Dentistry at the University of Hong Kong. “On top of knowing the clinical outcomes like stability and possible risks of the two procedures, this study reflected how the surgical procedures may impact their quality of life from different dimensions,” she added.

The study included 98 patients, of which half received IVRO and the other half received SSRO. Their quality of life was assessed by two self-administered questionnaires preoperatively and postoperatively at two weeks, six weeks, three months, six months, 12 months and 24 months. Using this data, the researchers analysed the longitudinal changes in the patients’ quality of life up to two years after the operation.

The study found that the oral health-related quality of life in patients in both IVRO and SSRO groups was significantly better three months postoperatively and continued to improve steadily. Additionally, it was found that patients who underwent the surgery at a younger age had a better oral health-related quality of life during the postoperative period.

A patient with mandibular prognathism. (Image: University of Hong Kong)

The study also reported that both groups experienced a greater physical impact of the interventions in the early postoperative period. Social functioning, emotion and mental health specifically negatively affected patients in the IVRO group. Both physical and mental health-related quality of life of patients in both groups had returned to baseline or improved by two years after the surgery.

When comparing the two procedures, it was found that the patients in the SSRO group experienced earlier improvement in their oral, physical and mental health-related quality of life, already showing signs of improvement two weeks after the surgery. The researchers suggested that this could be related to earlier mobilisation and function of the jaw and not having to undergo intermaxillary fixation.

“It is encouraging to see that the correction of mandibular prognathism improves the patients’ quality of life,” said lead researcher Dr Mike Yiu Yan Leung, a clinical associate professor in the faculty’s Division of Oral and Maxillofacial Surgery. “The study confirms that SSRO appears to offer earlier improvement of the patients’ quality of life after orthognathic surgery because of better function,” he added.

The study, titled “Comparison of the quality of life changes of patients receiving sagittal split ramus osteotomy or intraoral vertical subsigmoid osteotomy for mandibular prognathism”, was published in the April 2023 issue of Clinical Oral Investigations.