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REVIEW ARTICLE
Year : 2023 | Volume
: 14
| Issue : 1 | Page : 4-10
The post spinal surgery syndrome: A review
R Ramnarayan1, Bipin Chaurasia2
1 Department of Neurosurgery, New Hope Hospital, Chennai, Tamil Nadu, India
2 Department of Neurosurgery, Neurosurgery Clinic, Birgunj, Nepal
Correspondence Address:
Bipin Chaurasia
Neurosurgery Clinic, Birgunj
Nepal
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/jcvjs.jcvjs_118_22
Abstract Post spinal surgery syndrome(PSSS) has always been considered only for the pain it causes. However, many other neurological deficits do happen after lower back surgery. The aim of this review is to look into the various other neurological deficits that could happen after a spinal surgery. Using the keywords, foot drop, cauda equina syndrome, epidural hematoma, nerve and dural injury in spine surgery, the literature was searched. Out of the 189 articles obtained, the most important were analyzed. The problems associated with spine surgery have been published in the literature but are much more than the failed back surgery syndrome and cause more discomfort to the patients. To bring about a more sustained and collective awareness and understanding of these complications following spinal surgery, we encompassed all these complications under the heading of PSSS.
Keywords: Back pain, failed back surgery syndrome, spine surgery
Introduction 
Low back pain (LBP) is one of the most common degenerative disorders. In 2010, Hoy et al.[1] defined LBP as pain in the area on the posterior aspect of the body from the lower margin of the twelfth ribs to the lower gluteal folds with or without pain referred into one or both lower limbs that lasts for at least 1 day. Out of all 291 conditions studied in the Global Burden of Disease 2010 Study, LBP ranked first in terms of disability, and sixth in terms of the overall burden. The global point prevalence of LBP was 9.4%. Prevalence and burden increased with age. A similar study in Lancet[2] by the global burden disease (GBD) 2016 disease and injury incidence and prevalence collaborators showed that globally, LBP, migraine, age-related and other hearing loss, iron-deficiency anemia, and major depressive disorder were the five leading causes of years living with disability in 2016, and among this LBP contributed the highest. The treatment of LBP is both medical and surgical. Conservative methods include medications, bed rest, physical therapy, and epidural steroids. If these do not produce effective pain relief, then the patient could be offered surgery. The usual types of surgery for degenerative spinal disorders include discectomy with or without laminectomy and with or without fusion, percutaneous procedures, and spinal fusion techniques.
Review of literature
Post spinal surgery syndrome, previously known as failed back surgery syndrome (FBSS) refers to a condition whereby patients have persistent pain or develop new pain after undergoing spinal surgery. There have been many definitions of FBSS but the most practical is the one by the International Association for the Study of Pain, that defines FBSS as lumbar pain of unknown origin either persisting despite the surgical intervention or appearing after surgical intervention for spinal origin pain originally in the same topographical distribution.[3] The incidence of lumbar spine surgery in the UK is 5 in every 10,000 people and failure rates of spinal surgery is quoted as ranging between 10% and 40%. The average age of FBSS was 50 years and 50% are female patients. However, 78% of FBSS were on work disability compared to many other chronic pain conditions.[3]
FBSS is now considered a constellation of symptoms and has a varied etiology.[4],[5] In a recent study, Baber and Erdek[4] have described the current thinking in FBSS. The etiology was tabulated into preoperative and postoperative causes. The preoperative causes included smoking, obesity, preexisting psychiatric disorders, and cause of the pain (lumbar stenosis vs. disc herniation). Postoperative causes include progression of degeneration and biomechanical causes including arachnoiditis. A recent concept introduced by Bordoni and Marelli[6] is also very interesting. In their study, they analyzed the causes of FBSS. They postulated that the dysfunction of the diaphragm had a very important role in FBSS. Diaphragm dysfunction would lead to alterations in the biomechanics of the lumbar spine, with less proprioceptive abilities, less movement of the vertebrae, and reduction of functional collaboration of tissues that are involved in the proper functioning of the lumbar area; less stimulation of baroreceptors by the diaphragm and an alteration in the perception of pain. The diaphragm itself could be a source of pain, due to the change of its proprioceptors or irritation of the phrenic nerve and the vagus nerve.
Baber and Erdek[4] also tabulated the diagnostic workup in FBSS. These included a detailed history and clinical examination and radiological investigations including magnetic resonance imaging (MRI) and Computed tomography (CT) scans. Discography and diagnostic injections also have a role in the diagnostic pathways. Another extensive article by Chan and Peng[7] also described the algorithm for managing patients with FBSS. They stressed the fact that patients should be managed by an interdisciplinary team with medications, psychological therapy, exercise therapy, interventional procedures, and surgical procedures playing a role. They also tabulated a detailed management plan in these cases. A similar attempt was made by Schofferman et al.[8] to provide a distillation regarding the diagnosis of FBSS. They opined that the proper treatment of patients with FBSS depends on a precise and accurate diagnosis. With a careful history, examination, imaging studies, psychological evaluation, and diagnostic injections, a diagnosis can be reached in over 90% of patients. The most common diagnoses are foraminal stenosis (25%–29%), painful disc (20%–22%), pseudarthrosis (14%), neuropathic pain (10%), recurrent disc herniation (7%–12%), facet joint pain (3%), and sacroiliac joint pain (2%). Psychological factors are always present and may help or hinder. Common psychological diagnoses include depression, anxiety disorder, and substance abuse disorder. Diagnostic injections are very useful for facet joint pain, Sacroiliac Joint (SIJ) pain, and discogenic pain; they may also be used to confirm a putative neural compression as a cause of pain.
Radiological investigations remain a mainstay in assessments of FBSS. Previously X-rays and CT scan were the routine preferred investigation, but now the mainstay is MRI. Gadolinium-enhanced T1-weighted images allow differentiating disc herniation from postsurgical fibrosis.[7] In addition to lumbar MRI examination, a CT scan is helpful in visualizing osseous changes within the spine including facet changes, and assessing the osseous dimensions of the canals. Dhagat et al.[9] analyzed 30 postoperative symptomatic patients of FBSS. Of these, 26 had undergone surgery for degenerative disc disease and four had spinal fixation surgery for spondylolisthesis or trauma. They found that 16 patients had recurrent/residual disc herniation, six had epidural scar tissue, three patients had concomitant recurrent disc herniation and scar tissue, two had evidence of postsurgery arachnoiditis, two patients had postoperative discitis and one patient had implant failure. Recently, MR neurography (MRN) has been introduced as a diagnostic method in FBSS.[10] This is because nerve injuries are challenging to detect on conventional lumbar spine MRI. 22/25 patients had previous lumbar MRI. The most common imaging findings were neuroforaminal stenosis in 22.6% on MRI and neuropathy in 22.9% on MRN. Lumbar MRIs were inconclusive in 36% (8/22). MRN detected 63% (52/83) more findings and changed the diagnosis and treatment in 12% and 48% of FBSS cases, respectively. Favorable outcomes were recorded in 40%–67% of patients following MRN-guided treatments.
Many studies have shown the importance of psychological work in patients with failed back syndromes. Celestin et al.[11] studied pretreatment psychosocial variables as predictors of outcomes following lumbar surgery. They found a positive relationship between one or more psychological factors and poor treatment outcomes in 92.0% of the studies reviewed. In particular, presurgical somatization, depression, anxiety, and poor coping were most useful in helping to predict poor response to lumbar surgery. Older age and longer pain duration was also predictive of poorer outcome in some studies, while pretreatment physical findings, activity interference, and presurgical pain intensity were minimally predictive. Cho et al.[12] opined that 30%–40% of population aged 10–65 years report that back pain occurs on a monthly basis and in 1%–8% this interferes with work. It can be deduced that psychosocial factors, including insurance benefits are of importance for this variation. Neither nonoperative nor surgical procedures have a major impact on the capacity for work in this substantial minority of backache sufferers. Pending compensation and delays in the settlement are important additional features in claimants for compensation. For patients with unproven diagnostic labels such as “pain-behaviour,” no evidence exists that any type of surgery is cost-effective.
The management of FBSS is a very complex process and requires a very good teamwork of neurosurgeons, pain physicians, psychologists, physiotherapists, and other therapists. Chen and Peng in 2011[7] developed an algorithm for the assessment and management of patients with FBSS. The patients should be assessed by an interdisciplinary approach. A detailed history and clinical examination should be done including details of the pain history. MRI should be repeated in all patients. Correctable factors such as a misplaced pedicle screw compressing a nerve root or incomplete removal and persistent compression of a nerve root or even wrong levels should be identified and appropriate surgery offered. Detailed psychosocial assessment should be done in other patients and appropriate measures should be instituted. Patients should be managed by an interdisciplinary team with medications, psychological therapy, exercise therapy, interventional procedures, and surgical procedures playing a role. When deciding on which procedures may be efficacious in FBSS patients, it is useful to determine if the pain is predominantly axial or radicular. For those patients with predominantly axial pain, diagnostic blockade may be performed to determine if the pain is arising from the zygapophysial joints or the sacroiliac joints. If there is a positive response to lumbar medial branch blocks, radiofrequency rhizotomy may then be performed for longer-lasting analgesia. For suspected discogenic pain, the clinician may consider lumbar provocation discography. Revision surgery should only be undertaken if a lesion amenable to surgical intervention is present. For those patients with predominantly radicular pain, epidural injection of steroids under fluoroscopic guidance may be achieved through several routes. If there is a positive response, repeated injections may occur at an appropriate time interval. If epidural injection is unsuccessful, percutaneous epidural adhesiolysis may be considered especially if adhesions are the cause. For those patients with severe axial pain not responding to more conservative medical measures, intrathecal drug delivery systems may be considered. A trial of spinal cord stimulation (SCS) is to be strongly considered in all patients with radicular pain who have failed the more conservative measures.
Cho et al.[12] looked at neuropathic pain as part of FBSS. Usually, medicines are very effective including gabapentin with or without epidural steroids. Although medications may be effective to some degree, many patients continue experiencing intolerable pain and functional disability. Only gabapentin has been proven effective in patients with FBSS. Percutaneous epidural adhesiolysis has also shown good clinical outcomes but the effect is short-lived and adverse effects are sometimes intolerable. SCS is generally accepted to improve chronic back and leg pain (CBLP), physical function, and sleep quality. Although the cost-effectiveness of SCS has been proved in many studies, its routine application is limited considering that it is invasive and is associated with safety issues. Sebaaly et al.[13] reviewed the etiology, evaluation, and treatment of FBSS. They postulated that the etiology of FBSS is preoperative, operative, or postoperative factors. The evaluation of patients with FBSS symptoms should ideally initiate with reviewing the patients' clinical history and detailed clinical examination and imaging. They suggested that treatment should be initially nonoperative and include non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants, and spinal infiltration. Surgical management of FBSS should be reserved for patients with a documented anatomic or pathologic cause for their pain and/or with failed medical treatment. As stated above, the success rate of the surgery decreases with every reoperation. They suggested that in recurrent disc herniation, with the first recurrence best was microdiscectomy and the second recurrence, posterior fusion with anterior grafting.
Baber and Erdek[4] outlined a plan of action for patients with FBSS. Conservative management including physical therapy and medication management is the cornerstone of first-line management of FBSS. Physical therapy can help the patient optimize gait and posture and can improve muscle strength and physical function. Other conservative measures involve psychotherapy measures including stress reduction and cognitive behavioral therapy. Finally, noninvasive procedures including acupuncture and scrambler therapy can be used to minimize the pain associated with FBSS. These conservative measures should be done in conjunction with medication management to optimize pain relief. The usual drugs used include gabapentin, antidepressants, NSAID and in selected cases opioids. Epidural steroid injections are used in many patients. Many studies have shown the effectiveness of epidural steroids in FBSS.
Adhesions are another very important cause of FBSS. These adhesions may cause back and leg pain by compressing nerve roots, decreasing range of motion in the back and inducing pain with movement. Adhesions may contribute to or cause 20%–36% of FBSS cases.[4] Adhesiolysis is possible either by using an epidural injection of hyaluronidase with saline and steroids. In a systematic review performed by Helm et al.,[14] seven randomized control trials and three observational studies demonstrated that Level I or strong evidence that percutaneous lysis of adhesions is efficacious in the treatment of chronic back and extremity pain, with weaker Level II or III evidence for epiduroscopy based on one randomized controlled trial (RCT) and three observational studies. Other techniques such as radiofrequency ablation of nerves, facet block injections, and sacroiliac joint injections are often used to provide sustained relief. These are generally done by pain specialists and so are not discussed further in this chapter.
Ganty and Sharma[15] proposed an algorithm for managing FBSS recently. Patients' motivation, expectations, and understanding of their condition should be taken into account when considering treatment options. It is mandatory to exclude any curative treatment options (disc fragments, new disc herniation at another level, spinal instability, or significant spinal stenosis), before considering the patient for pain relief or pain management options. Pain in FBSS is a mix of both neuropathic and nociceptive types. First, a comprehensive biopsychosocial assessment is performed. If needed psychologist and psychiatrist may be involved. MRI and CT scan is done to rule out other treatable causes such as adhesions or recurrent disc prolapse. Ideally, the need for further surgery should be ruled out before the patient is referred to the pain physician. The patient is initially treated with medical and physical measures including analgesics, antidepressants other physical and psychological measures. Three to 4 weeks is a good time for this. If this fails then other interventional procedures like epidural steroids may be recommended. Many patients do benefit from these methods. In those who do not improve, then higher levels of pain management are needed. If the pain is of a noxious type and predominantly involves the back only then intrathecal morphine (ITM) delivery systems can be given. If the pain is of neuropathic type with radiating pain the SCS is the best option.
Surgical revision for FBSS is associated with a high morbidity with correspondingly low rates of success.[16],[17],[18],[19],[20],[21],[22],[23],[24] Arts et al.[25] demonstrated only a 35% success rate, 15 months after an instrumented fusion for the treatment of FBSS. These poor results demonstrate that the surgical option for the treatment of FBSS should be limited to last-line therapy. However, there are times when reoperation is mandated, such as loss of bowel or bladder function, motor weakness, and progressive neurological impairments from spinal cord injury, with relative indications being severe incapacitating radiculopathy, pseudoarthrosis, instability, and surgical hardware malfunction.
Amirdelfan et al.[26] did a literature review of the treatment options for FBSS. The publications were arranged hierarchically according to the North American Spine Society's guidelines as RCTs, prospective studies, retrospective chart, and systematic reviews. The review focused on studies with at least 20 FBSS patients and 6-month follow-up. They found that evidence is weak for medications and reoperation, but strong for active exercise and interventional procedures such as adhesiolysis. The strongest evidence for long-term treatment is for SCS, showing favorable Level I RCT results compared with conventional medical management and reoperation. Kapural et al.[27] did a systematic review for clinical evidence for (SCS) for FBSS. They concluded that SCS is a safe and efficacious treatment for FBSS. Recent technological developments in SCS offer even greater pain relief to patients with an improvement in quality of life. Frey[28] did a systematic review of SCS in patients with FBSS to demonstrate clinical and cost-effectiveness. They concluded that the effectiveness of SCS in relieving chronic intractable pain of FBSS indicated the evidence to be Level II-1 or II-2 for clinical use on a long-term basis. Grider et al.[29] did a systematic review of RCTs of SCS in chronic spinal pain by reviewing available literature. They concluded that there is significant (Level I to II) evidence of the efficacy of SCS in lumbar FBSS. There is moderate (Level II to III) evidence for high-frequency stimulation; there is limited evidence for adaptive stimulation and burst stimulation. Waszak et al.[30] analyzed the clinical use, quality of life, and cost-effectiveness of SCS in FBSS. They insisted that the patient selected for SCS implantation should have a stimulation trial and only if this is successful, permanent surgical implantation of a spinal stimulator should be performed. They found that complications due to SCS in FBSS are generally mild but reports of epidural abscess, thrombosis, meningism, cerebrospinal fluid leak, and hemorrhage do exist. Other complications include lead migration, local wound infection, pocket pain, and loss of therapeutic effect. The benefit of SCS in FBSS treatment has been confirmed only in patients presenting radicular pain, with no efficacy evident in patients suffering from axial pain with a small radicular component. The weight of evidence indicates that SCS seems to be cost-effective, at least in the long term. Taylor et al.[31] studied the extent to which pain relief in CBLP following SCS is influenced by patient-related factors, including pain location, and technology factors. There was substantial statistical heterogeneity in the level of pain relief after SCS. The mean level of pain relief across studies was 58% at an average follow-up of 24 months. Multivariable meta-regression analysis showed no predictive patient or technology factors. SCS was effective in reducing pain irrespective of the location of CBLP.[31],[32] This review supports SCS as an effective pain-relieving treatment for CBLP with predominant leg pain with or without a prior history of back surgery.
Collectively, psychological and social issues are common among pain patients. Campbell et al.[32] opined that when psychosocial issues are identified, treatment can be tailored to address these challenges, thereby improving the likelihood and speed of recovery. Psychological evaluations typically should include the assessment of sensory, affective, cognitive, and behavioral components of the pain experience, expectations of the benefit of an implanted device, and identification of personality and psychosocial factors that can influence treatment outcome. In addition to psychological assessment, quantitative sensory testing procedures offer another valuable resource in forecasting who may benefit most from SCS.
There have been two randomized control trials and one observational study on the effective of SCS in FBSS. North et al.[33] compared reoperation versus SCS in FBSS. Charge data for 42 patients were collected and the details were analyzed. They concluded that SCS was less expensive and more effective than reoperation in selected failed back-surgery syndrome patients, and should be the initial therapy of choice. SCS is most cost-effective when patients forego repeat operation. Should SCS fail, reoperation is unlikely to succeed. The study by Kumar et al.[34] randomized 100 FBSS patients with predominant leg pain of neuropathic radicular origin to receive SCS plus conventional medical management (SCS group) or conventional medical management alone (CMM group) for at least 6 months. Crossover after the 6-month visit was permitted, and all patients were followed up to 1 year. Compared with the CMM group, the SCS group experienced improved leg and back pain relief, quality of life, and functional capacity, as well as greater treatment satisfaction. Hence, the conclusion was that in selected patients with FBSS, SCS provides better pain relief and improves health-related quality of life and functional capacity compared with CMM alone. Zucco et al.[35] conducted an observational, multicenter, longitudinal study of patients with predominant leg pain refractory to CMM to see the cost-effectiveness and cost-utility of SCS. They result suggests that in clinical practice, SCS + CMM treatment of FBSS patient's refractory to CMM provides good value for money. Finally, the National Institute of Clinical Excellence (UK) produced a guideline in 2008[36] which recommended SCS as a treatment option for adults with chronic pain of neuropathic origin who: continue to experience chronic pain (measuring at least 50 mm on a 0–100 mm Visual Analog Scale) for at least 6 months despite appropriate conventional medical management, and who have had a successful trial of stimulation as part of the assessment.
As already mentioned FBSS is often a complex condition where the pain may be only axial and only nociceptive.[37],[38],[39],[40],[41],[42],[43],[44] In such a scenario, SCS may not be the best method of treatment. ITM given through a drug delivery system has been tried in these cases as well as in failed SCS treatment. Schuchard et al.[37] reported a retrospective analysis of 50 patients to test the efficacy and safety of intra-spinal opioids for patients with nonmalignant pain. They found out that long-term intrathecal opioids are efficacious, practical, and safe for the treatment of nonmalignant pain syndromes. FBSS patients respond similarly to intra-spinal analgesia as the patients with neuropathic pain, while the group with mixed pain from other non-FBSS causes respond similarly to the nociceptive pain patients. Raphael et al.[38] looked at the long-term experience with implanted intrathecal drug administration systems for failed back syndrome by retrospective analysis. They reported that the majority of quality of life measures improved significantly in the FBSS group. The mean dose of diamorphine increased for the first 2 years but did not change 2–6 years' postimplant, averaging 4.5 mg/day. Hence, the conclusion was that spinal drug administration systems appear to be of benefit in alleviating pain in the failed back syndrome. Another prospective study about the long-term treatment of 30 patients with nonmalignant pain treated with intrathecal infusion of morphine was done by Lara et al.[39] The mean intensity of pain reduced from 9.5 to 4.6 and the mean daily dose of morphine necessary for pain control became constant after the 6th month of treatment. Side effects were more frequent at the beginning and became tolerable after the 1st month of treatment. There was improvement in the quality of life measured by SF-36 (30.8–49.6) and in all dimensions of the treatment of pain survey, except for working capacity. A third retrospective analysis of all patients with lumbar FBSS who were trialed with a combination of hydromorphone and bupivacaine was done by Galica et al.[40] The objective of this study was to determine the overall outcomes of continuous infusion IT trials and factors influencing the long-term success of intrathecal (IT) therapy in patients with chronic intractable pain postlaminectomy. Significant positive correlations were found between pretrial oral opioid intake and end-of-trial hydromorphone dose and hydromorphone dose escalation at 12 months and 24 months. Hence, the conclusion was patients with refractory LBP due to FBSS who underwent a successful combination IT trial with hydromorphone and bupivacaine infused through a temporary IT catheter had significantly improved pain intensity scores following permanent implant.
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