Findings of a multicentre, prospective study conducted through the International Spine Study Group (ISSG) and presented at the 27th Annual Meeting on Advanced Spine Techniques (IMAST 2020) have detailed the complication rates associated with surgical treatment of adult cervical deformity. The findings may be useful in ongoing efforts to improve the safety of care in the treatment of spinal deformity, suggested the study’s author, Justin S Smith (University of Virginia, Charlottesville).
“Adult cervical deformity surgeries are often complex and they tend to have high rates of complications, however there have been few reports that have described these complications, and most are retrospective or based on small case series, from a single surgeon or institution,” Smith told the IMAST audience in the introduction to his presentation. The objective of the study was to assess the rates of complications associated with surgical treatment for adult cervical deformity with a minimum one-year follow-up, and also to assess for demographic, clinical and surgical parameters associated with the occurrence of complications.
Patients aged 18 or above at the time of enrolment and with cervical deformity including cervical kyphosis between the C2–C7 vertebrae, a C2–C7 sagittal vertical axis ≥4cm, chin-brow vertical angle ≥10 degrees or cervical scoliosis (with a coronal Cobb angle >10 degrees) were eligible for inclusion in the study. Those with active tumour or infection, or acute trauma, were not included.
The team used standardised data collection forms to collect information on demographics, surgical treatment, and outcomes measures, as well as for complications which were classified as minor or major and as perioperative, early or delayed. The study focused on patients with a minimum of one-year follow-up.
A total of 167 patients were identified for inclusion, 133 of whom had a minimum one-year follow-up. Of these, 62% were women, with a mean age of 61.5 years and 84% had at least one comorbidity. The most primary diagnosis was degenerative kyphosis (45%), followed by iatrogenic kyphosis (17%) and cervical kyphoscoliosis (6%). Smith detailed that 20% of patients were treated using an anterior only approach; 47% had a posterior only approach, and the remaining 35% had a combined approach. The mean number of levels fused in patients was 8, whilst almost 20% had a high grade osteotomy.
Outlining the complication rates, Smith explained that overall there were 132 complications affecting 55.6% of patients. Most of these occurred within one of five categories: cardiopulmonary, neurological, dysphagia/GI (see slide), radiographic and infection. Within the cardiopulmonary category, respiratory failure and cardiac arrest were the most common complications, whilst in the neurological category, he explained that new nerve root motor or sensory deficits were most prevalent.
Within the dysphagia/GI category, the most common complication was dysphagia which occurred in approximately 11% of patients. Furthermore, the most common radiographic complication was distal junction kyphosis, occurring in 9%, and lastly, Smith noted that the most common infectious complication was deep wound infection occurring in 6%. “Importantly the 34 patients that did not have a minimum of one-year follow-up did not have complication rates that were significantly higher than the patients that had a minimum of one-year follow-up,” he added.
Looking at complications and baseline parameters, he commented that there were only two baseline parameters significantly associated with occurrence of complications, and added that older patients, and patients with a greater C2–C7 sagittal vertical axis (SVA) were more likely to experience complications. Pointing to surgical parameters, Smith stated that a greater number of fusion levels was the main associated factor. In terms of the surgical approach, the posterior-only and combined approaches had greater baseline C2–C7 sagittal vertical axis, as well as less baseline cervical lordosis, more fusion levels, and greater estimated blood loss. The anterior-only and combined approaches had significantly increased dysphagia rates, but there were no other differences in complication rates based upon surgical approach, he explained.
Summarising the findings, Smith detailed that among the 133 patients, 56% had at least one complication at a mean follow-up of 1.8 years. The most common complications were dysphagia (12%), distal junction kyphosis (9%), respiratory failure (6%), deep wound infection (6%) and new nerve root deficit (5%), he commented, adding that there were “significantly higher rates of complications in patients who were older and had greater C2–C7 SVA, as well as those with an increased number of fusion levels”.
Discussing the significance of the study, he said: “These findings may be useful for treatment planning, patient counselling, developing techniques to try to reduce complications, and overall ongoing efforts to improve the safety of care.”