With the ageing of the global population, the incidence of OVF is increasing [9]. OVF does not always manifest refractory back pain, neurological symptoms are sometimes occurred. Study of such clinical phenomenon is rare. Ito et al. [10] reported that 55% of patients with OVF had neurological symptoms. However, the case series included the OVF of upper lumbar and thoracic spine. Kim et al [5] reported that the incidence of newly developed leg pain following OVF was 25%, in which 86.7% of cases were IEP-type fractures of lower lumbar spine. In our study, we observed the incidence of radiculopathy of lower limb following acute OVF of lower lumbar spine is 3.53% (22/624), in which compressive fracture account for 45.4% of all fracture types, and the involvement of IEP is more susceptible to suffer radiculopathy of lower extremity (72.7%). The mechanism of neurological impairment following OVF of lower lumbar spine can be ascribed to: 1) migrated bony fragments invade the foraminal space, resulting in direct NR compression, 2) decreased foraminal height secondary to vertebral body collapse, mainly the posterior height, exacerbate the primary foraminal stenosis, 3) posterior branches irritated by the narrowing foramen, leading to pain in their distribution areas as a radicular or somatic referred pain [11]. In this case series, we managed 16 patients who had no significant preexisting degeneration with stand-alone PKP, in which recovery of posterior height of vertebral body is essential to observing satisfactory clinical results.
In this research, we observed 11 patients (50%) had preexisting degeneration, as degeneration are frequently occurred in lower lumbar spine. Based on the preexisting LDH or foraminal stenosis, the symptoms of radiculopathy following OVF may be worse, which need more aggressive intervention. Surgical treatment of such clinical scenario in geriatric population is challenging, as open decompression with instrumented stabilization harbour a high risk of significant complications and hardware failure due to comorbidities and poor bone quality related to advanced age [12]. Kim et al. [5] reported successful management of 15 elderly patient who suffered radiculopathy following OVCF with PKP/PVP only. However, they only included stable vertebral fracture (A1 type), also, they did not detailedly introduce the condition of preexisting degeneration. Zhao et al. [7] reported the application of PKP and full-endoscopic surgery in dealing with a elderly patient with preexisting foraminal stenosis and suffered radiculopathy following OVF. Satisfactory clinical outcome was observed with 3-month follow-up. Similarly, Lin et al. [13] reported 15 cases with radiculopathy following OVF, which were treated with PKP/PVP and full endoscopic surgery. They observed improved back pain and neurological symptoms with at least one-year follow-up. In our study, two patients with preexisting LDH/foraminal stenosis were managed with PKP and full-endoscopic surgery, while one patient with LDH who had poor general condition underwent radiofrequency ablation after initial PKP. During the follow-up period, satisfactory outcomes with no recurrence were observed in these patients.
Minimally invasive surgical intervention seems to be an optimal option for the elderly with poor general condition and multiple comorbidities. However, unstable fracture can be frequently occurred in osteoporotic population, even after a minor trauma [14]. Lee et al. [15] reported four elderly patients with unstable AO type III fracture suffered delayed-onset radiculopathy resulted from refracture of primary operated vertebral body and retropulsed bone fragment 2 to 16 weeks after PKP surgery. All four patients underwent another operation (posterior decompression and instrumentation), in which one died of postoperative intracranial haemorrhage. Refracture rate of cemented vertebrae after vertebroplasty was high and was reported to be 63% of osteoporotic patients [16]. Moreover, adequately restoring the posterior vertebral body height and avoiding over-restoration of anterior vertebral body height are important to reduce refracture rate of cemented vertebrae [17]. Revision surgery should be avoided as much as possible on account of poor general condition of the elderly. In our study, we managed most of the unstable fracture, mainly AO type 3, with one-stage open surgery. In the four patients with burst fracture, three patients with fracture of both end-plates were managed with short-segmental fixation and fusion, while one patient with fracture of superior end-plate and ASA III was carefully managed with PKP. In addition, decompression procedure was spared in case satisfactory reduction can be observed after instrumentation (e.g. patient NO. 7). The complication rate in this study was 9.1%, including CSF leakage and wound infection. All patients with complications were recovered after careful management. No delay-onset complication was observed.
Based on the observation and treatment experience from the present study, here we provide a flow chart for helping to decide an optimal surgical strategy in managing radiculopathy following acute OVF in the lower lumbar spine [Figure 6].
There are several limitations should be mentioned. First, we excluded the patient with follow-up period less than 12 months, accordingly, only 22 patients were observed in the present research. Larger sample sizes will be needed to further elucidate the incidence of new-onset radiculopathy following acute OVF, as well as make our conclusions more convincing. Second, the follow-up period is short with an average of 17.42 ± 9.62 months. However, each enrolled patient underwent at least one-year follow-up. Third, we did not evaluate the imagological information at patient’s final follow-up due to data loss, which is also important to further assess the long-term clinical outcome.