Surgery for patients with ESRD is challenging for surgeons. In a literature review, surgical complications, such as cardiovascular diseases, volume disturbance, coagulopathy, metabolic acidosis, and electrolyte imbalance were observed more frequently in ESRD patients who had undergone major surgery [9, 10].
Gajdos et al. followed 1506 ESRD patients who had undergone general surgery between 2005 and 2008. They reported that dialysis patients had a significantly greater rate of both 30-day overall complications (28.6% vs. 10.7%, p < 0.001) and unplanned return to the operating room (18.5% vs. 4.9%, p < 0.001) than did non-dialysis patients [11]. Surgical outcomes of dialysis patients who underwent orthopedic surgery were also poor, especially in trauma cases. Patients with ESRD experienced mortality rates of up to 50% at one year following hip fracture. High infection or sepsis rates have also been reported [12,13,14]. In another study, Ackland et al. reported a series of 142 patients with chronic kidney disease (CKD) (stages 3 through 5) undergoing elective primary and revision total hip arthroplasty (THA) and total knee arthroplasty (TKA). The authors observed a two-fold risk of surgical complications, such as pulmonary, infectious, cardiovascular, and gastrointestinal complications, as compared with those of normal patients [15].
Eric Nyam et al. reported high surgical risk and complications in patients with ESRD who underwent spinal surgery. Their series report included 4109 participants with ESRD and 8218 patients without ESRD, all of whom were undergoing spinal surgery. The authors observed comparatively poorer outcomes for the ESRD patients: ESRD patients who underwent spinal surgery presented significantly greater in-hospital mortality than did patients without ESRD (10.17% vs. 1.39%, P < 0.0001). Moreover, different spinal surgery methods also influence on ESRD patients’ in-hospital mortality rates: operations on spinal cords and spinal canal structures had the greatest hospital mortality (14.87%) compared with spinal fusion (3.46%), excision, or destruction of intervertebral disc (3.01%) [4]. Decompression and instrumented spinal fusion are frequently used for the surgical treatment of DLD. Lumbar posterolateral fusion (PLF) and lumbar interbody fusion (IBF) are the two main techniques of instrumented spinal fusion. Both of these have been extensively studied in prior reports. McAnany et al. conducted a systematic review of 865 articles that revealed no significant differences in clinical outcomes (VAS, ODI), surgical information (operation time, estimated blood loss), complication rate, or fusion rate between the two groups [16].
However, no study appears to have discussed which fusion method is optimal for patients with ESRD. Using the traditional open method, high blood loss is common in instrumented lumbar surgery because the spine is a rich blood supply area [17]. Coagulopathy or even disseminated intravascular coagulation (DIC) may result in significant blood loss, which is fatal and may cause postoperative epidural hematoma or increase the risk of infection. According to a previous study, coagulation abnormalities were observed in 42.9% of patients with ESRD [18]. The mechanism of ESRD coagulopathy is that uremic toxins inhibit normal platelet function and platelet–vessel wall interactions [19]. This is why ESRD patients with hemodialysis dependence can experience greater blood loss during instrumented lumbar surgery. In our study, the amount of blood loss was significantly higher (780.0 vs 428.4 ml, p = 0.001) in the IBF group than in the PLF group. Since epidural bleeding is common during IBF surgery, these findings suggest that IBF could aggravate blood loss in ESRD patients undergoing instrumented lumbar surgeries.
The mean operation time was longer (210.9 vs. 178.3 min, p = 0.029) in the IBF group than in the PLF group in the current study, meaning that the patients in the IBF group were anesthetized for longer. General anesthesia is required for patients undergoing instrumented lumbar surgery; however, general anesthesia can be very difficult for anesthesiologists to administer to patients with ESRD. Hemodynamic instability is common in patients with ESRD following the induction of general anesthesia [20]. Hence, anesthesiologists must evaluate each patient’s fluid status consistently and adjust fluid therapy carefully; the longer the time under anesthesia, the greater the surgical risk. In this study, patients with ESRD who underwent interbody fusion for lumbar surgery required a longer operation time and had a higher incidence of complications. The surgeon should consider the shortcomings of the IBF technique in these patients before surgery.
The radiographic outcome in our study was assessed using the fusion rate. In a literature review, the fusion success rate in general patients was approximately 84–90% when using PLF and 90–95% when using IBF [21, 22]. Generally, the fusion success rate is slightly higher in IBF than in PLF in general populations. However, no study on the success rate of fusion in patients with ESRD appears to exist. Based on our results, the fusion success rate was better in the PLF group than in the IBF group, although the difference was not significant (65.2% vs. 58.8%, p = 0.356). When compared to general patients, the fusion success rate was significantly lower in ESRD patients. Patients with ESRD usually have osteoporosis and exhibit several metabolic and hormonal abnormalities, including decreased renal synthesis of 1,25(OH)2D3, hyperphosphatemia, hypocalcemia, increased secretion of PTH, chronic metabolic acidosis, and, more recently, 25(OH) vitamin D deficiency, which may affect bone growth and remodeling processes [23]. According to our study, the rate of fusion success was lower in the IBF group than in the PLF group, while the opposite was true in non-ESRD patients. We believe that the poor result in the IBF group was attributed to poor bone quality in the ESRD patients. In the IBF group, we observed two cases with posterior cage migration and four cases with cage subsidence. Based on a previous study, osteoporosis is an important risk factor for cage migration or subsidence [24].
Regarding surgical and medical complications of ESRD patients after undergoing instrumented spinal fusion, Puvanesarajah et al. reported that patients with late-stage renal disease that had undergone1–2 level posterolateral lumbar fusion had 1.6 times higher risk of experiencing a major medical complication within 3 months of surgery and 2.8 times increased risk of 1-year mortality when compared with patients without renal disease [5]. Our results show that both groups had high surgical complications (20.5% vs. 22.2%), including implant loosening and wound dehiscence, as well as medical complications (5.8% vs. 6.6%), including electrolyte imbalance and AV graft failure. However, there were no statistically significant differences in surgical and medical complications between the PLF and IBF groups.
In a literature review, there was no significant difference in clinical outcomes between PLF and IBF for DLD [16]. In our study, patients with ESRD underwent PLF or IBF, and both groups showed significant improvements in ODI and VAS scores compared to baseline, but there were no significant differences between the groups.
Our study does, however, have some limitations. First, the surgeons chose the surgical method at their own discretion, thus potentially influencing the results by selection bias. Second, radiographic fusion and instrumentation failure were not evaluated by dynamic radiographs (flexion-extension view) or computed tomographic assessment, which might decrease accuracy. Third, the DLD of the current study included degenerative spondylolisthesis, degenerative lumbar scoliosis, degenerative lumbar kyphosis, and isthmic spondylolisthesis. These heterogeneous cohorts might decrease the generalizability to the study population and interfere with the results.
