ABSTRACT
Background Conventional imaging is useful to assess interbody fusion by showing complete trabecular bony bridging, but has a low positive predictive value for pseudarthrosis. Because alterations of bone metabolism may precede structural anatomical changes on computed tomography (CT), we aimed to investigate the ability of fluorine 18 sodium fluoride positron emission tomography/computed tomography ( 18 F-NaF PET/CT) to identify pseudarthrosis after spinal fusion using surgical revision as the reference standard. Methods We retrospectively reviewed 18 F-NaF PET/CT scans performed between February 2019 and September 2020 in patients experiencing pain after spinal fusion. We included the 18 patients who underwent revision surgery for suspicion of pseudarthrosis. Five consecutive patients who were clearly fused on CT served as the control group. Results In the revision surgery group ( n =18), visual assessment by 18 F-NaF PET/CT revealed that all 22 cages with an increased 18 F-NaF uptake around intercorporal fusion material had mobility at revision surgery, whereas none of the fused patients ( n =5) showed uptake around cage/intervertebral disk space. Among the 18 patients with presumed aseptic pseudarthrosis, intraoperative cultures revealed surgical site infection (SSI) caused by Cutibacterium acnes ( C. acnes ) in seven patients (38.9%). There was a statistically significant difference in standardized uptake values and uptake ratios between the revision surgery and control groups ( p =5.3× 10 -6 and p =0.0002, respectively). Conclusions 18 F-NaF PET/CT imaging appeared as a useful tool to identify pseudarthrosis following spinal fusion. The unexpectedly high prevalence (38.9%) of SSI caused by C. acnes found in presumed aseptic patients supports the utility of intraoperative cultures in revision cases for pseudarthrosis, even without preoperative clinical suspicion of SSI.
ABSTRACT
STUDY DESIGN: Description of the technique and retrospective study of patients treated with unilateral extraforaminal lumbar interbody fusion (ELIF) for degenerative lumbar spinal disorders. OBJECTIVE: To investigate clinical and radiologic outcome of patients treated with unilateral ELIF. SUMMARY OF BACKGROUND DATA: Lumbar interbody fusion is the classic treatment for higher grades of degenerative disk disease or lumbar segment instability and is performed by posterior (PLIF), posterolateral, or anterior (ALIF) approaches. Those techniques are well established with known limitations and complications. Today, minimally invasive procedures generate more interest especially in terms of muscle damage to achieve better functional outcome. We introduce a unilateral extraforaminal fusion technique which respects neural as well as muscle structures aiming to preserve function. METHODS: Intraoperative and perioperative data, neurological status, Oswestry Disability Index, the Visual Analogue Scale for leg and back pain, and patient satisfaction were investigated preoperatively and at latest follow-up. Fusion status was controlled by x-ray and CT scans at a 6 months' follow-up investigation. RESULTS: A total of 107 patients [female/male: 67/40; average age, 52.8 (± 13.8) y] were included at a maximum of 31(± 9.4) months. Complications occurred in 4% of patients. Transient radicular pain was investigated in 16 patients. The Oswestry Disability Index and the Visual Analogue Scale for back and leg pain improved significantly. Patients showed a short hospital stay and high percentage of return to work ratio (70%). Fusion was achieved in 97% of patients. CONCLUSIONS: The unilateral ELIF fusion technique demonstrates encouraging clinical and radiologic midterm outcome that for some indications is comparable with established fusion techniques.
