Patient selection for the original spine surgery is of the utmost importance in preventing FBSS. It is essential that the proper operation is offered for the correct condition and that patients have reasonable expectations of their surgery. Herniated discs, spinal stenosis, foraminal stenosis, and unstable spondylolisthesis are straightforward indications. Less commonly, tumors, infection, and/or congenital issues such as a tethered cord and scoliosis may be present and warrant operation. Other conditions may be approached differently from surgeon to surgeon and often have higher patient dissatisfaction rates and success.

Additional preoperative factors that affect surgical outcome include revision surgery and insufficient candidate screening. In patients who had multiple revisions, the rate of epidural fibrosis and instability increased to greater than 60 % [4]. Additionally, patients must be counseled about reasonable expectations and informed that surgery will not resolve all of their symptoms. Proper counseling of expectations for an initial spine surgery may dramatically reduce the rate of FBSS [5]. For the remaining cases, it is important to ascertain what pain complaint remains following surgery when thinking of further treatment outcomes.

The patient’s psychological status is also an important preoperative factor that can strongly impact surgical outcome. It has been shown that depression and anxiety correlate with poorer outcomes [6]. Thus, the patient’s ability to cope with stress plays a paramount role in determining who will respond better to surgery. Pain questionnaires used to screen patients include the Pain Catastrophizing Scale (PCS) as well as the Minnesota Multiphasic Personality Inventory (MMPI) . The PCS score has been shown to significantly correlate with patients’ postoperative pain scores [7]. In addition, the MMPI-2 was shown to be a predictor of implantation status, showing that personality traits or disorders affect the decision-making process for therapy [8]. Unfortunately, economic and social factors also affect psychological status. Patients who are involved in the worker’s compensation and/or the litigation process may have less motivation to improve [9]. Another factor that has been found to affect surgical outcome is the weight of the patient. Patients who had normal body mass indices (BMI) were found to have higher scores on emotional well-being scales as well as better perceptions of their disease than those who were obese (BMI >25) [10–12].

Once an appropriately selected patient reaches the operating room for the correct procedure, other patient and surgical factors may predispose the patient to poorer outcomes. These include modifiable risk factors, such as smoking status, diabetes, and morbid obesity. Smoking is well known to impede fusion and wound healing and some surgeons refuse to perform these surgeries until the patient quits [11, 13, 14]. Additionally, diabetes and obesity significantly increase the risk for surgical site infections (SSI) and perioperative complications [15]. In diabetics, it is essential to ensure that their disease is as well controlled as possible with the help of their endocrinologist and/or primary care physician prior to surgery. Obesity often leads to longer dissection and surgery time which increases the risk for infection and deep vein thrombosis [16]. Other comorbidities related to the spine also need to be accounted for such as immunosuppression, rheumatoid arthritis, renal disease, and osteoporosis/osteopenia. All are associated with higher rates of major complications [15, 17–19]. Obesity may also necessitate changing routines in the operating room through the use of different tables or retractor systems that are less familiar to the surgeon [20].

Sometimes, findings intraoperatively may result in a less than ideal outcome. Specifically, multiple preoperative epidural steroid injections (ESI) can lead to scarring and difficulty with nerve root retraction [21, 22]. Calcified discs are often harder to remove and may result in greater root retraction and thus postoperative numbness and weakness [23].

Suboptimal surgical technique may also lead to postoperative issues. These include over-distraction of the disc space during fusion, irritation of the nerve roots, and inadequate or overly aggressive decompression [24]. Despite the shift toward more minimally invasive techniques in the past decade, there is no data suggesting lower rates of FBSS [25, 26]. Lastly, it is of course essential to ensure that the surgery was performed at the right level, and that the overall aim of surgery was accomplished by obtaining pre-, intra-, and postoperative imaging [27, 28].

Postoperative impediments to outcome may be due to patient, surgical, or disease factors. Patients may not be compliant with postoperative management. Often bracing or restrictions are implemented and patients do not comply. Though the use of bracing is often controversial, the patient who is noncompliant is likely to be involved in a series of activities that may hinder their surgical outcome. We often instruct patients that they have one chance to heal and should therefore adhere to activity restrictions for the designated length of time. It is their responsibility to take ownership of their health. Patients who are committed to their recovery and doing the right thing such as not smoking, losing weight, and participating in physical therapy when indicated have better outcomes [29–31].

Despite the surgeon and the patient’s best work however, complications do occur. Most commonly, an infection or cerebrospinal fluid (CSF) leak can present in the perioperative period. CSF leaks not only predispose the patient to more infections, but also cause headaches, photophobia, nausea, diplopia, and tinnitus [32, 33]. Because SSIs may lead to deeper infections and more serious problems when left unrecognized, these issues must be handled promptly with rapid evaluation of the patient at the onset of signs or symptoms. Additionally, recurrent disc herniations are most common in the initial postoperative period [34]. Patients who have recurrent radiculopathy after a period of relief should be assessed clinically and with imaging.

Disease progression may lead to issues in long-term follow-up. These include the development of scarring (epidural fibrosis, arachnoiditis), anatomical instability, and adjacent level disease. Epidural fibrosis may contribute to persistent pain felt by up to 36 % of FBSS patients due to the tethering of nerve roots [1, 35]. Postsurgical fibrosis at the nerve roots was found to be associated with a higher incidence of recurrent pain following surgery. In a randomized, double-blind clinical trial, patients with extensive peridural scarring were 3.2 times more likely to experience recurrent pain than those with less fibrosis [36]. The researchers suggested that the encasement of the nerve roots with fibrotic tissue was causing pain by increasing neural tension, impairing axoplasmic transport, and constricting blood supply [36]. Perineural scarring often is hyperintense on MRI with gadolinium as opposed to recurrent disc which is hypo- or iso-intense. Additionally, a loss of disc height and anatomic stability after a discectomy can lead to vertical stenosis and compression of nerve roots [28]. This puts patients at risk for foraminal stenosis, disc herniation, or instability [37]. In the long term, adjacent segment disease (ASD) may occur due to hypermobility and increased biomechanic stress on the adjacent segments [38]. It is important to note that FBSS includes all patients with pain after surgery in either the back or the leg or both. Thus, it is likely that some cases of FBSS are really just the natural course of the disease, rather than a failure of surgery as the name implies. It is important to realize that a technically accurate and well-performed surgery does not guarantee success in terms of pain management, as surgical indications for surgery can stem from neurological compromise, as well as prevention of deterioration.