Narrative Review on Postoperative Pain Management Following Spine Surgery
Article information
Abstract
Postoperative pain is an inevitable consequence of spine surgery, yet there remains no universal consensus on the optimal pain management strategy. The complexity of spine procedures, coupled with patient variability, necessitates a multifaceted approach to pain control. Over time, numerous strategies have emerged, each with varying levels of effectiveness. Pharmacological approaches, including multimodal analgesia, local anesthetic infusions, and gabapentinoids, provide relief for both acute and chronic pain. Additionally, perioperative strategies such as enhanced recovery after surgery (ERAS) protocols have demonstrated benefits in optimizing pain control and recovery outcomes. Beyond pharmacological interventions, physical therapy has become a cornerstone of postoperative pain management, aiding in functional recovery and reducing reliance on medications. For patients with refractory or chronic pain, neuromodulatory techniques such as spinal cord stimulation and intrathecal injections offer alternative solutions. Despite the breadth of evidence-based strategies available, limitations persist, including opioid dependence, the complexity of multimodal regimens leading to suboptimal compliance, and cases of refractory pain. These challenges underscore the importance of tailoring pain management approaches to individual patient needs, ensuring a balance between effectiveness and safety. This narrative review of evidence seeks to explore the multifaceted nature of pain management following spine surgery, highlighting the challenges and evolving strategies in optimizing patient outcomes.
INTRODUCTION
Spine surgical procedures, such as discectomies, laminectomies, and spinal fusions have been crucial to addressing pain and restoring function in patients with a variety of conditions. While these procedures often alleviate a significant portion of symptoms, pain is still highly prevalent following spine surgery. Postoperative pain can be classified as acute versus chronic. Acute postoperative pain can impact length of hospital stay as well as overall recovery. As such, it is crucial to address postoperative pain at its initial stages to promote rehabilitation, improve patient outcomes, and ensure patient satisfaction. As with nonoperative pain duration, acute postoperative pain is generally classified as any pain symptom that persists after the procedure. The chronicity of the postoperative pain symptoms dictates the prognosis of recovery and should be taken into consideration formulating a treatment plan. Treatment of chronic postoperative spinal pain symptoms is often more challenging and requires more advanced therapies. While there have been previous publications regarding postoperative pain management, there remains no consensus on the approach to postoperative patients. One of the most sentinel publications regarding postoperative pain management was a multisociety clinical practice guidelines (CPGs) published nearly a decade ago [1]. Despite its rigor in development, the multisociety CPGs’ primary focus was on acute inpatient postoperative pain management. This narrative review intends on presenting existing evidencebased pain management strategies following spine surgery in both the acute and chronic conditions; encompassing application of enhanced recovery after surgery (ERAS) protocol, pharmacologics, the role of physical therapy (PT), and interventional procedures.
METHODS
A literature search of PubMed was performed using key terms of “postoperative spine pain management” OR “postoperative spine rehabilitation,” OR “postoperative spine pain medications,” OR “postlaminectomy syndrome,” OR “failed back surgery syndrome,” OR “persistent pain syndrome.” The database was searched for publication dates from 2000–2025.
Studies specific to managing spine-related postoperative pain in both acute and chronic phases of recovery were included. For treatment-related study searches, randomized controlled trials (RCTs), randomized crossover trials, quality guidelines, metaanalyses, and systematic reviews were the primary foci. Prospective and retrospective cohort studies were searched if there were no RCTs and systematic reviews available. Exclusion criteria included manuscripts that were (1) descriptive publications on surgical technique, (2) studies including the adolescent or pediatric subjects, (3) treatments not viewed as standard of care (investigational/experimental) in the United States, (4) treatments not directly addressing postoperative surgical pain, (5) case reports and/or white papers, (6) unpublished data or abstract presentations.
An initial total of 13,961 records were identified through database searches. After removing duplicates, titles and abstracts were screened independently by 2 reviewers. Full-text articles were assessed for eligibility based on predefined inclusion and exclusion criteria. After screening for eligibility assessment, 82 studies were included in the qualitative synthesis. After data curation, manuscripts were then separated by subject matter and corresponding pain treatments, addressing either acute versus chronic postoperative spinal pain. Manuscripts were reviewed by each author specific to standard of care treatments; if none were present, then recommendations were provided based on empirical evidence. Furthermore, a proposed algorithm was synthesized based on evidence-based treatment options presently available (Fig. 1). Given the scope of this narrative review, and the heterogeneity of many of the studies included, a meta-analysis was not performed.
Proposed pain management algorithm following spine surgery. w/o, without; IV, intravenous; PCA, patient-controlled analgesia; PT/OT, physical therapy/occupational therapy; MRI, magnetic resonance imaging; CT, computed tomography; ESI, epidural steroid injection; SI, sacroiliac; IT, intrathecal; HEP, home exercise program.
ACUTE PHASE PAIN MANAGEMENT
Prior to consideration of pain management options, it is critical to evaluate the patient’s postoperative pain symptoms. Postoperative pain is an inevitable sequelae, but there may be clinical signs and symptoms that may suggest a complication from the surgical procedure itself (Fig. 1). A comprehensive neurological examination during the acute postoperative phase can help in ruling out sequelae related to the surgical procedure itself (i.e., bleeding, infection, dural tear, nerve or spinal cord injury), which might require further work-up and intervention.
Due to the complex nature of spine procedures and the variability of individual patient conditions, multiple treatments may be employed to treat and manage pain following spine surgery. One widely adopted strategy is multimodal analgesia, which employs multiple classes of medications with complementary mechanisms of action to optimize pain relief during the patient’s recovery period [2]. While multimodal analgesia provides targeted postoperative pain management, the importance of addressing pain at a perioperative level has led to the development of more comprehensive systems of care. In the late 1990s, a group of colorectal surgeons in Denmark began experimenting with a new model of care under the leadership of Professor Henrik Kehlet [3,4]. The model, which came to be known as ERAS, represented a major shift in how surgeons practiced perioperative care and encompassed a variety of evidence-based practices that all aimed to improve surgical outcomes and drastically shorten patients’ hospital stay durations [5]. The protocols aim to reduce surgical stress, maintain physiological function, and accelerate recovery time though pre-, intra- and postoperative interventions. Since their beginnings in colorectal surgery, the ERAS protocols have been adapted to a variety of surgical specialties, and adherence to the protocols has time and again been shown to improve patient outcomes [6].
1. ERAS Protocols
The ERAS protocols are structured into 3 perioperative phases, each with their own evidence-based interventions and techniques (Fig. 1) [5,7]. The preoperative phase focuses on preparatory counseling, cessation of alcohol and tobacco, optimization of organ function, and strategic nutrition management, including reduced fasting times and carbohydrate loading. During the intraoperative phase, emphasis is put on minimally invasive surgical techniques, balanced fluid administration, and appropriate regional anesthesia techniques to minimize opioid use. Postoperatively, the priority lies in early mobilization, prompt return to oral nutrition, and multimodal pain management strategies that further minimize opioid use. Throughout the perioperative stage, maintenance of normothermia, avoidance of fluid overload, and prevention of nausea and emesis are essential components.
While adoption of ERAS has been slower in spine surgery compared to other specialties, it has gained significant momentum in the past decade [6,8]. Multiple systematic reviews have demonstrated that ERAS protocols result in significant reduction in length of hospital stay without increasing complication rates [9,10]. The University of Miami developed an innovative ERAS protocol for lumbar interbody fusion, employing an “ultra-MIS” technique with endoscopic visualization and percutaneous instrumentation. This permitted conscious sedation with propofol and ketamine infusion rather than general anesthesia, eliminating associated cardiopulmonary and metabolic disturbances. Their published series demonstrated significant improvement in clinical outcomes with minimal complications and an average length of stay of just 1.4 days [11]. A comprehensive ERAS spine protocol from the University of Louisville incorporated multiple elements across 19 different studies, showing significant reductions in length of stay and improved pain scores. Implementation of ERAS elements also resulted in cost savings, with one study reporting a 15.2% reduction ($3,444) per procedure [10].
Naftalovich et al.’s literature review [12] identified significant variation across protocols but noted common foundations of multimodal analgesia, early mobilization, and nutritional optimization. Their analysis of protocols from various institutions revealed consistent use of acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), gabapentinoids, and local anesthetics, though with varying dosing regimens. A recent comprehensive review by Bansal et al. [13] demonstrated ERAS effectiveness across diverse spine procedures, including anterior cervical surgeries, deformity correction, and spinal tumor resections. They identified key benefits including reduced length of stay, decreased opioid requirements, and cost reductions without increasing complication rates.
Implementation of ERAS in spine surgery requires structured multidisciplinary coordination. Based on evidence from multiple institutions, successful implementation begins with establishing a dedicated ERAS team comprising surgeons, anesthesiologists, nurses, and physical therapists. Preoperative optimization should address nutritional status (targeting albumin levels >3.5 g/dL), smoking cessation, and glycemic control. Standardized multimodal analgesia should begin preoperatively with acetaminophen, gabapentinoids, and NSAIDs where appropriate. Intraoperatively, teams should prioritize minimally invasive techniques when feasible and maintain normothermia and euvolemia [12,13]. Postoperatively, institutions should implement structured protocols prioritizing nonopioid analgesics with opioids reserved for breakthrough pain. Mobilization goals should be procedure-specific, beginning within hours of surgery when appropriate. Regular auditing with dedicated ERAS coordinators tracking metrics including length of stay, pain scores, and opioid consumption is essential. Protocols should be tailored to specific spine procedures rather than applying a universal approach across all spine surgeries [10,14].
Despite promising outcomes, spine surgery presents unique ERAS challenges. Elsarrag et al. [9] noted that high pain levels, prolonged hospital stays, and slow return to function are often inevitable consequences of spinal procedures and can directly conflict with ERAS principles. In particular, early patient mobilization is frequently impossible with spinal ailments, highlighting that ERAS elements must be incorporated on a case-by-case basis. Exact elements of ERAS and implementation strategies vary between subtypes of spinal surgery, but efficacy in length of stay, postoperative pain, complications, and costs has been demonstrated in lumbar, cervical, and adolescent scoliosis procedures [8,15-18]. As expected with the nature of spinal surgeries, less complex procedures, demonstrated in the study Soffin et al. [19] on minimally invasive microdiscectomy, tend to show the most significant improvements with ERAS protocols.
While the investigations and reviews listed previously indicate improved outcomes, varying strategies for implementation of ERAS in spine surgery settings reduces direct comparability of ERAS spinal studies. As spine-specific guidelines continue to evolve, standardized protocols tailored to specific procedure types represent the logical next step for widespread ERAS implementation in spine surgery [20].
2. Pharmacological Treatments
Given the variability in ERAS implementing, tailoring pharmacological treatments to each individual remains a cornerstone of perioperative pain management following spine surgery. Traditionally, opioids have been used as a first-line medication for pain relief; however, they pose risk of opioid dependency and tolerance as well as opioid-induced hyperalgesia [21]. Opioids function by binding to mu opioid receptors, a type of G-protein coupled receptor found in the central nervous system. Binding of the opioid ligand triggers a cascade of intracellular signaling pathways that mediate not only pain relief but also trigger the mesolimbic reward system, which produces sensations of pleasure through dopamine release [22]. Therefore, opioids can become highly addictive when used as a primary analgesic. As such, opioids should be administered in the smallest effective dosage for the shortest duration possible. Opioids are best administered in conjunction with other nonopioid medications, such as NSAIDs, acetaminophen, gabapentinoids, etc.
In the context of acute pain management following spine surgery, proper prescription of opioids is a major area of improvement. A 2020 qualitative assessment of opioid prescribing practices following spine surgery revealed significant interprovider variation in interpretation of opioid prescribing guidelines. Additionally, there was a noted deficiency in postoperative opioid prescribing handoff between surgical and postoperative primary care teams [23]. Addressing such inconsistencies is crucial to optimizing acute multimodal analgesia to provide more effective pain management both immediately following surgery and into the recovery period.
NSAIDs function by inhibiting cyclooxygenase, an enzyme that converts arachidonic acid into prostaglandins. Prostaglandins are hormone-like lipids that produce inflammatory mediators, dilating and increasing blood flow to sites of inflammation. By blocking prostaglandin production, NSAIDs reduce inflammation and consequently provide pain relief. Some limitations of NSAID usage include the potential for mucosal damage through the upper and lower gastrointestinal tract, which can also increase the risk of bleeding. Specifically, in the context of spine surgeries, NSAIDs may impair recovery time due to inhibition of osteogenesis [24]. A 2019 meta-analysis found that NSAID usage may increase the risk of delayed union or non-union in healing bones, with a more pronounced effect in older patients [25]. A more recent systematic review and meta-analysis concluded that incorporating NSAIDs into the postoperative regimen held no increased risks of complications. In their analysis, there were 7 fusion studies reporting on arthrodesis, all of which showed significantly lower odds of fusion after NSAIDs use. However, after subgrouping according to smoking, the difference was not found to be statistically significant [26]. When implementing postoperative NSAID use in spine patients, one should consider all comorbidities. Given conflicting information, NSAIDs are best avoided in patients who smoke and have undergone a fusion procedure with instrumentation. Use of NSAIDs in the presence of other anticoagulants is contraindicated. NSAIDs are best implemented in those patients with minimally invasive decompressive procedures (i.e., laminectomy).
Acetaminophen is a nonopioid analgesic alternative that inhibits prostaglandin production in the central nervous system in a similar mechanism as NSAIDs. This medication specifically reduces pain and fever, but does not have as strong anti-inflammatory effects as NSAIDs. When combined with NSAIDs and opioids in a multimodal approach, acetaminophen can enhance pain relief while minimizing the need for opioid usage. Efficacy of intravenous acetaminophen (paracetamol) administration for postoperative pain control has been well described following various types of surgery [27]. In regard to postoperative spine surgery analgesia, the results are mixed. In one study, the authors showed no difference in opioid use in patients given intravenous acetaminophen [28]. This conflicts with a prior retrospective analysis which showed the intravenous acetaminophen cohort used less opioids [29]. In a single center randomized trial, there was found to be no statistically significant difference between postoperative pain ratings, post anesthesia care unit morphine milligram equivalents, quality of recovery-15 scores, and recovery time when comparing oral versus intravenous acetaminophen use following spine surgery [30]. In a recent meta-analysis of 5 RCTs, it was concluded that intravenous acetaminophen did reduce opioid consumption in patients having undergone spine surgery, though GRADE quality of evidence was low to moderate [31]. Implementation of intravenous acetaminophen may be used as a possible alternative or adjunct to traditional postoperative analgesia with cost admittedly being the main limiting factor.
Gabapentinoids, like gabapentin and pregabalin, are another class of medication that have been commonly used to treat neuropathic pain. Gabapentinoids inhibit voltage-gated Ca2+ channels in the central nervous system to prevent the release of excitatory neurotransmitters. Traditionally, they have been used as anticonvulsants; gabapentin was initially approved for use as a muscle relaxant and antispasmodic in 1993. In 1998, gabapentin was found to be a significant analgesic of neuralgic pain through a randomized control trial of diabetic neuralgia patients, though it has been used off-label for many other neuropathic painful conditions [32]. Since then, the U.S. Food and Drug Administration (FDA) has also endorsed gabapentin use in neuropathic pain management.
There have been several systematic reviews and meta-analysis of RCTs published with overwhelming consensus showing effective use of gabapentin, and pregabalin, for acute postoperative spine pain. Liu et al. [33] showed that gabapentinoids were associated with reduced pain scores at 6, 12, 24, and 48 hours. Similarly, gabapentinoids have been associated with a reduction in cumulative morphine consumption at 24 and 48 hours [34]. Pooled results from meta-analysis performed by Yu et al. [35] demonstrated both gabapentin and pregabalin could significantly reduce the postoperative narcotic consumption when compared to placebo. Efficacy of gabapetinoids for postoperative pain management not only applies to fusion surgeries but also showed replicable results with laminectomy and discectomies [36,37]. Twenty-seven randomized clinical trials with 1861 patients were included in the systematic review and network meta-analysis studying the appropriate dosages of gabapentin and pregabalin for peri- and postoperative pain control [38]. Compared with placebo, the visual analogue scale pain score was lowest with gabapentin 900 mg per day, followed by gabapentin 1,200 mg per day, gabapentin 600 mg per day, gabapentin 300 mg per day, pregabalin 300 mg per day, pregabalin 150 mg per day, and pregabalin 75 mg per day.
In a retrospective data analysis, it was recently observed that coadministration of gabapentin with opioids was associated with an increased risk of abuse and respiratory depression [39]. Increased risk of opioid-related death in these patients may be related to other factors including increased pain and chronicity of pain that are often associated with need for concomitant gabapentinoid use. Results have not been reported on adverse events following concomitant short-term use of opioids and gabapentinoids. Consequently, when using gabapentinoids and opioids as part of a multimodal regimen, it is important to monitor the duration of use.
In addition to oral consumption of pain medications, analgesics have been delivered via local anesthetic infusion or patient-controlled analgesia (PCA) pumps. Local anesthetic infusions are usually delivered to the subfascial or subcutaneous space at the surgical site to provide continuous, passive infusion of analgesic to the surgical area in order to reduce local inflammation and pain [40]. In contrast, PCA pumps take a more systemic route and are delivered intravenously thereby providing the patient with greater control over their analgesic dose schedule based on their pain levels. Epidural analgesia (EA) has been often compared to the use of PCA pumps following spine surgery. Though EA has been used successfully in controlling pain, its use has fallen out of favor due to equivocal results with intravenous pain medication use, and with EA having significantly more side effects [41]. There is additionally conflicting data showing lower amounts of opioid consumption with EA compared to PCA. The routine use of epidural anesthesia for lumbar spine surgery has too many risks and offers very little advantage over PCA.
Continuous local anesthetic infusion has been commonly employed as a mode of acute pain management following spine surgery. A 2009 retrospective, case-control study reviewed the efficacy of local anesthetic infusion, via the ON-Q PainBuster, an elastomeric pump [40], to the subfascial aspect of the surgical site following lumbar fusion surgery. This study found profound acute pain relief, indicated by lower opioid consumption, particularly in postoperative days (PODs) 1, 2, and 3 such that patients with the ON-Q PainBuster demonstrated a decreased morphine consumption of 41.2%, 50.1%, and 47.1% compared to patients in the control group without local anesthetic infusion [42]. Such a marked reduction in opioid consumption indicates a strong advantage to using local anesthetic infusion during early phase acute pain management. When more effective early pain control is able to reduce opioid consumption, patients also experience more minimal opioid-related side effects, like nausea and vomiting, which can ultimately improve functional recovery outcomes. However, one limitation in this study is the lack of a saline infusion device in the control group. Thus, placebo effect may have contributed to the analgesic effect in patients with the ON-Q PainBuster.
Furthermore, one important consideration before utilizing continuous local anesthetic infusion may be the type of spine surgery received. The main goal of a local anesthetic delivery to the wound site is to reduce local inflammation and reduce pain signaling. This was noted in a study by Elder et al. [42] following lumbar fusion surgery, however the study suggested that there was less efficacy following minimally invasive spine surgeries. Kim et al. [43] conducted a prospective comparative study between patients undergoing a conventional versus a more minimally invasive mini-open approach to posterior decompression and fusion of L4–5 segments for spinal stenosis. Results of this study demonstrated decreased serum creatinine kinase and inflammatory cytokines during POD 1–3 for the minimally invasive approach. As such, in surgical approaches where local inflammation has been minimized, there may not be as significant of a pain relief observed using local anesthetic infusion. This presents a major area of continued research to provide the most effective acute pain management strategies for different types of spine surgery. As evidence remains equivocal with variability and limitations in existing data, some clinicians have moved away from PCA and On-Q pumps towards regional anesthesia techniques.
Erector spinae plane (ESP) blocks are a novel analgesic technique described in 2016 to treat thoracic neuropathic pain [44]. ESP blocks have been recently found as an effective mode of postoperative acute pain management following spine surgery and have thus been routinely incorporated in lumbar surgeries. The efficacy of the ESP block was demonstrated in a 2022 RCT in which patients undergoing lumbar spine surgery received either an ultrasound-guided ESP block or no block [45]. Patients were provided with PCA devices for self-administered pain management via a 0.06 mg/kg bolts dose of tramadol. The effectiveness of pain management was evaluated based on postoperative morphine consumption and numerical rating scale (NRS) scores for pain. Results demonstrated that patients receiving the ESP block had significantly lower opioid consumption, 12.71 bolus deliveries versus 19.37 bolus deliveries (p=0.000), and reported lower NRS scores than patients who received standard anesthesia with no ESP block.
A 2019 prospective, randomized, controlled clinical trial investigated the perioperative effect of local anesthetics in patients undergoing lumbar spine fusion surgery and found a decreased opioid and anesthetic consumption and reduced postoperative length of hospital stay. Patients were randomized into an ultrasound-guided lateral thoracolumbar interfascial plane (TLIP) block with 0.375% ropivacaine or a control group that received 0.9% saline [46].
These findings were reaffirmed in a more recent RCT comparing the effects of TLIP block with ESP blocks [47]. Patients in the ESP group demonstrated significantly lower total opioid consumption and lower NRS scores compared to patients in the TLIP group. Both analgesic techniques were shown to be effective but ESP provided more effective analgesic effect in patients following spine surgery. The significant reduction in opioid consumption represents a major advantage to incorporating ESP into postoperative pain management to combat ongoing issues with opioid dependence and tolerance. Furthermore, reduced NRS pain scores indicate greater levels of patient-reported pain control which can ultimately lead to improved overall recovery and patient satisfaction following spine surgery [48].
In summary, a thorough understanding of pharmacodynamic drug interactions in multimodal analgesia allows the administration of smaller medication doses to mitigate any adverse side effects and proper choice of analgesic technique based on the type of spine surgery received. There is insufficient evidence available to suggest specific guidelines in regards to pharmacological treatments, but review of the literature suggests when using a multimodal analgesia the following consideration be taken:
• Concomitant use of low dose opioids, intravenous acetaminophen, and gabapentinoids may provide optimal pain control following spine surgery with minimal pharmacologic-related events [49]. Careful monitoring of duration of use and dosage is recommended when using gabapentin with opioids given the increased risk of abuse and respiratory depression.
• Dosing of gabapentin has been shown most optimal at 900 mg per day (300 mg 3 times a day) or pregabalin 300 mg per day. While relatively safe, gabapentin and pregabalin should be tapered to these doses to monitor any side effects. One may consider starting gabapentin at 300 mg per day (100 mg 3 times a day) or pregabalin 150 mg per day (50 mg 3 times a day).
• Muscle relaxants may be utilized as an adjunct to opioid and gabapentinoid medications. Caution however must be taken given the propensity for these medications to result in sedations, somnolence and altered mental status, particularly in the elderly population.
• NSAIDs may be used with caution, but best practices suggest they should be avoided due to potential impediment of healing and fusion. NSAIDs are also contraindicated in those patients with blood thinners, previous stroke, or heart attack. Use of NSAIDs may be limited to patients with no comorbidities and are best implemented in those undergoing minimally invasive decompressive procedures.
• Recent FDA approval of suzetrigine provides a possible alternative to gabapentinoids, although further studies are necessary specific to the use of postoperative pain.
• Many clinicians have moved away from use of PCA and OnQ pumps, although their use still remains an option particularly when oral analgesics are not well tolerated.
• Regional blocks are becoming more prominent and may allow for less reliance on traditional oral or intravenous analgesia. Regional anesthesia is often favored for procedures like lumbar microdiscectomy and decompression where the surgeon can clearly see and operate on the affected area. Regional anesthesia may be preferable for patients with conditions that make general anesthesia risky, such as those with heart problems or respiratory compromise.
• Pharmacological and interventional treatments within the acute postoperative phase are critical to allow for optimal patient experience, early mobilization to prevent deconditioning, allow tolerance to perform activities of daily living and fully participate in PT.
3. Role of Postoperative Rehabilitation
The role of PT as a standard of care in postoperative management following spine surgery has gained prominence over many decades since it was first endorsed as an integral component of care during the first world war [50]. PT quickly gained credibility and recognition as it offered noninvasive musculoskeletal manipulations as a means to relieve pain, improve mobility, and improve quality of life.
There is ample evidence supporting the effectiveness of PT in reducing pain following different types and intensities of spine surgery. In a systematic review of 45 randomized control trials, active rehabilitation programs reduced pain intensity, improved disability and quality of life after lumbar spinal stenosis, lumbar spondylolisthesis, and lumbar disc herniation [51]. The use of PT after other spine surgeries such as lumbar decompression [52,53], spinal fusion [52,54], endoscopic lumbar discectomy [55,56], and microdiscectomy [57-59], has been documented. Meanwhile, a few studies suggest that PT does not significantly impact patient-reported outcomes (PROMs). For instance, a retrospective cohort study of patients who attended or did not attend PT after lumbar fusion found that PT did not significantly impact PROMs [60].
While PT is widely recommended to patients following spine surgery, there is a lack of consensus about rehabilitation protocols including the timing, duration, and intensity of exercise intervention [61,62]. Table 1, detailed below, presents a summary of PT protocol variations.
Variation in the type, initiation, and duration of physical therapy
Many studies report a 12-week duration benchmark when examining the effect of rehabilitation on postoperative pain [63-65]. Typical exercises for the 12-week rehabilitation protocol include back extensor strength and endurance training, trunk and lower extremity exercises [63,65]. Other studies have used an 8-week benchmark with similar exercise regimen [64,66,67]. Notably, even when exercise protocols are specified, exercises may change based on participants’ needs.
Variation in the initiation of PT also exists. Though many studies report different times for starting PT (Table 1), few have purposefully investigated the effect of initiating PT at an earlier or later time postsurgery. A meta-analysis of studies investigating the safety and effectiveness of early rehabilitation found evidence for significant reduction in pain after starting PT within 4 weeks of spine surgery. However, these studies did not appropriately compare different PT starting times as they included controls with no or sham PT. Meanwhile, Oestergaard et al. [64] investigated the effect of initiating PT at 6 weeks or 12 weeks postsurgery and found that starting PT early at 6 weeks resulted in lower reduction in back pain compared to starting at 12 weeks. Both groups underwent four 2-hour sessions of cognitive behavioral PT (CBPT) with exercises for active stability training of the truncus and large muscle groups. A follow-up study by Oestergaard et al. [68] also found that the 6-week group had significantly greater functional disability compared to the 12-week group. Evidence contrary to a later PT start time is sparse. LeBlanc et al. [69] investigated the effect of starting PT 1–2 weeks postsurgery versus 4–6 weeks postsurgery. While both groups had significant reduction in their numeric pain rating scale, the earlier group had a greater reduction. Fewer studies have considered the effect of preoperative rehabilitation. Nielsen et al. [70] compared a control group which received postoperative pharmacologic pain management to an intervention group exposed to 6- to 8-weeks of individualized, preoperative home-based training program and intense mobilization on the day of surgery followed by postoperative 30 minutes mobilization exercises twice daily for 5 days in addition to pharmacologic pain management. The intervention group experienced significantly lower pain at admission to surgery, discharge, and 1, 3, and 6 months after surgery.
In addition to protocol variation in the initiation and duration of PT, studies also differ in their approach to PT (Table 1). While some studies focus on exercise therapy alone [41,42,44,63]. others endorse cognitive CBPT - a psychomotor (or psychosocial) therapy incorporating cognition, behavior, and motor relearning [64,66,71-75]. Undergirding this approach is the belief that patients’ fear of pain during mobilization is a predictor of poor patient outcome after surgery [76]. Patients enrolled in CBPT are provided the opportunity to share their experiences of pain and physical incapacity with other patients while learning cognitive coping strategies for pain management [66,71-73]. Even among studies that focus on CBPT, protocols may differ. In an RCT of 104 patients, Abbott et al [71]. presented a 12-week psychosocial protocol which included a 90-minute outpatient CBPT session every 3 weeks. In the interim, participants were encouraged to perform self-directed lumbopelvic stabilization exercises and closed kinetic chain function exercises which include supine hip flexion seated over-head elastic band raises, wall supported semisquats and lunges, among others. Meanwhile, another CBPT protocol provided each participant with a 30-minute phone call with a physical therapist once a week for 6 weeks whilst they were encouraged to perform exercises at home [72].
Although variations in PT protocols may seem unsystematic, they do not indicate poor effectiveness. Rather, they reflect the ongoing pursuit of optimal strategies to enhance patient outcomes. As a result, various emerging PT modalities have been introduced. In addition to CBPT, other tools and approaches include transcutaneous electrical nerve stimulation (TENS), aquatic therapy, manual therapy, and therapeutic ultrasound, among others. Using electrical currents to stimulate afferent nerve receptors and reduce nociceptor cell activity, TENS has been reported to effectively reduce pain following spine surgery [77,78]. Similarly, aquatic therapy has also been found to be effective in reducing pain after spine surgery. An RCT of 28 participants who underwent lumbar fusion showed that participants who received 2 sessions of 60-minute aquatic training, with three 60-minute sessions of home exercises each week for 6 weeks had significantly lower pain compared to those who only performed home exercises [79]. Ultrasound therapy is yet another strategy used to taper pain. It has been cited as the most commonly used electro-physical tool, with evidence supporting its effectiveness for nonspecific lower back pain [80]. However a Cochrane review suggested that it is unclear whether therapeutic ultrasound with exercise versus exercise alone results in better outcomes [81]. Manual therapy has also been shown to reduce leg and back pain [82,83].
Overall, the literature provides ample evidence supporting the use of PT after spine surgery. Therefore, PT has become the standard of care, particularly following more extensive open spine surgical procedures. Regarding PT, the evidence suggests the following:
• Early initiation of PT is paramount to any patient who has undergone spinal surgery, showing faster recovery periods and mitigating any deconditioning or muscle atrophy. PT may start at approximately 4–6 weeks postoperatively.
• Prior to starting PT, it is recommended that the surgeon evaluate the patient for any complications or sequelae from the surgery (i.e., wound infection, bleeding, poor healing, acute neurological deficits).
• PT approaches used to address postoperative spinal pain are heterogenous. Regardless of the specific types of exercises the therapist should incorporate exercises that the patient is able to tolerate.
• There is no consensus on use of modalities; however, they are generally well tolerated, have minimal adverse effects and may provide additional analgesia during therapy sessions. Modalities may include but are not limited to TENS, aquatic therapy, manual therapy, massage, and therapeutic ultrasound.
• Up to 12 weeks of PT may be offered to the patient following spine surgery. During this time, the therapist and patient should develop and tailor an individualized home exercise program.
CHRONIC POSTOPERATIVE PAIN MANAGEMENT
Chronic postsurgical pain was first defined in 1999 by Macrae [84], described as a “pain that develops after surgical intervention and lasts at least 2 months; other causes of pain have to be excluded, in particular, pain from a condition preceding the surgery.” An updated definition was later proposed by Werner and Kongsgaard [85] in 2014, as “pain persisting at least 3 months after surgery, that was not present before surgery, or that had different characteristics or increased intensity from preoperative pain, localized to the surgical site or a referred area, and other possible causes of the pain were excluded (e.g., cancer recurrence, infection).” There remains no agreement as to what designates “chronic” pain after surgery. Many surgeons will often arbitrarily use 6 or 12 months as the time in which neurological recovery should be noticed. These numbers are often used in other neurological conditions such as stroke or spinal cord injury.
When pain persists despite sufficient postoperative time and treatments, medications can be used long-term to palliate patients’ pain. The challenge of long-term pharmacological use is that the efficacy of currently available medication for treatment of neuropathic pain is variable [86]. In a recent systematic review and meta-analysis, 229 studies looked at the number needed to treat (NNT) for various classes of medications for treating neuropathic pain [86]. Trial outcomes were generally modest; NNTs were 6.4 (95% confidence interval, 5.2–8.4) for serotonin-noradrenaline reuptake inhibitors, mainly including duloxetine (nine of 14 studies); 7.7 (6.5–9.4) for pregabalin; 7.2 (5.9–9.21) for gabapentin, including gabapentin extended release and enacarbil; and 10.6 (7.4–19.0) for capsaicin high-concentration patches. NNTs were lower for tricyclic antidepressants, strong opioids, tramadol, and botulinum toxin A, and undetermined for lidocaine patches. The lack of replicable response to these medications proposes a challenge, resulting in polypharmacy and opioid use which come with increased risks for adverse events, as previously discussed. Recognizing the limitations of chronic pharmacological management, much attention has now turned towards interventional pain treatments.
There are several published studies that assessed the efficacy of epidural injections following spine surgery. One limiting factor in assessing the data is the heterogeneity in study design across the studies. As part of this, many of the studies utilized noncorticosteroid injections. For those that utilized steroids, there have been conflicting results, with some studies showing poor short and long-term response, while others showed clinically significant and durable pain relief.
In a comparative study Manchikanti et al. [87] compared percutaneous adhesiolysis versus caudal epidural steroid injection (ESI). While showing that adhesiolysis could be effective treatment in postlaminectomy syndrome, the study showed only a 12% response rate for caudal ESI. The poor outcomes following caudal ESI is not consistent with a future study by the same lead author. In 2012, Manchikanti et al. [88] conducted a RCT on 140 patients were randomly assigned to 1 of 2 groups. The study compared caudal epidural injections with local anesthetic (lidocaine 0.5%) versus caudal epidural injections with 0.5% lidocaine 9 mL mixed with steroid (Celestone). Combined pain relief (≥50%) and disability reduction was recorded in 53% of the patients in the local anesthetic group, and 59% of patients in the steroid group at 12 months.
Manchikanti et al. [89] similarly designed a study to evaluate the effectiveness of cervical interlaminar epidural injections of local anesthetic with or without steroids in providing effective and long-lasting relief in patients with cervical postlaminectomy syndrome. This analysis included 56 patients. Significant pain relief (≥50%) was demonstrated in 71% of patients who received anesthetic only, and in 68% of patients who received anesthetic with steroids at 12 months.
Two separate trials evaluating epidural injections of steroids (prednisolone acetate) versus saline alone produced contrasting results: one noted no benefit at 120 days and the other reported a reduction in pain at 18 months after multiple epidural injections [90,91].
Although there have been conflicting results, the use of epidural injections to address postoperative pain has been shown to have potential long-term benefits following spine surgery. Epidural injections should be reserved after sufficient time has passed to allow for surgical healing and in the case of fusion, bony maturity. Although relative risk is low, care should be taken when performing epidural injections at a previously decompressed level as well as instances where there is hardware.
Intrathecal (IT) pain pumps may be an alternative for patients that continue to require a consistent amount of analgesics postoperatively. The advantage of IT delivery is bypassing the gastrointestinal tract, which allows faster onset of analgesia and decreased gastrointestinal side effects from the medications (i.e. GI discomfort). IT pain pumps can infuse both opioid and nonopioid medications (i.e., Ziconitide) for analgesia. Pain pumps are typically refilled every 2–3 months, depending on frequency and amount of medications used, which may also decrease the burden of monthly visits for medication refills. There are still inherent risks associated with IT pain pumps which include pump related issues, overdose, reaction to medications, and improper refill of the pump/human error [92].
Neuromodulation techniques, such as spinal cord stimulation (SCS), have emerged as an option for managing chronic pain following spine surgery without necessarily relying on pharmacological treatment. SCS involves the implantation of electrodes that deliver electrical impulses to the spinal cord, modulating pain signals. Prior to implantation, a SCS trial is often recommended. Historically one of the first studied applications of SCS was in patients who had previous spine surgery diagnosed with postlaminectomy syndrome (otherwise referred to as failed back surgery syndrome, persistent spinal pain syndrome). Postlaminectomy syndrome connotes the presence of pain in the lower back, legs or both, despite previous spine surgery.
One of the first published RCTs by North et al. [93], showed SCS provided greater pain relief and patient satisfaction with less analgesic use and loss of function than reoperation for treatment of chronic radicular pain after prior lumbosacral spine surgery. In the same year North published prospective data showing decreased pain and analgesic use following SCS implantation. In 2 separate publications following the same patient group, Kumar and North published RCT data both at 6- and 24-month follow-up [94,95]. The studies showed SCS and CMM is more effective at pain reduction, improved function, and health-related quality of life than CMM alone at 24-month follow-up with greater patient satisfaction. There have been more recent studies using novel waveforms (aside from traditional tonic stimulation) that showed efficacy in the post-laminectomy patient population, including high frequency stimulation and burst waveforms [96,97].
Other applications of neuromodulation may show promise for possible treatment of postlaminectomy pain symptoms; these include dorsal root ganglion stimulation and peripheral nerve stimulation of the medial branches (both restorative and palliative). While there are anecdotal accounts of both pain reduction and increased function in the application of these novel targets, there has yet to be any high-level studies to support more widespread use.
The use of interventional procedures for chronic pain following spine surgery has been shown to improve pain symptoms, functionality and quality of life. These therapies, however, must be implemented in a judicious manner so as to optimize outcomes and to minimize overutilization.
• Epidural injections have the potential to provide long-term relief for both neuropathic pain after spine surgery. The durability of pain improvement has been shown in certain studies to be over a year, though other studies suggest that there is minimal efficacy overall. Nevertheless, with there being limited alternatives, epidural use has been widely accepted. When utilizing epidural injections, follow-up is essential to determine their effectiveness. Repeat epidural injections may be considered if they provide at least 50% reduction of pain, which is consistent with standard of care of use of epidural injections in nonsurgical spine patients.
• In cases where there are back or leg pain symptoms following spinal surgery, the use of neuromodulation has been well established as a form of nonpharmacological based form of treatment. Novel and subperception waveforms, improvements in technology, have improved patient experience and reported outcomes. Neuromodulation trials are common practice in many countries and may provide additional confidence of the efficacy of the therapy prior to implantation.
• In situations where a patient cannot tolerate oral medications, or contrastingly is opioid-tolerant, there may be selective indication for an IT pain pump. While not necessarily specific to postoperative spinal pain, it has been proven to provide significant analgesia in patients with recalcitrant postoperative pain. The same care and caution should be taken when infusing opioids through the IT pain pump.
FUTURE CONSIDERATION IN POSTOPERATIVE SPINAL PAIN MANAGEMENT
There still remain gaps in knowledge which need to be addressed to improve postoperative pain management. This includes further advancements in pharmacologics. Already we have seen recent data on acute postoperative pain control through selective inhibition of Nav1.8 voltage-gated sodium channels expressed in peripheral nociceptive neurons. There are similar other nonopioid options presently being studied worldwide. The advances in oral pharmacologics may extend to medications that may be provided both intravenously and intrathecally.
One promising approach in multimodal analgesia is to blunt the rewarding effects of opioids through activation of the endocannabinoid system. In a recent preclinical experimental study with mouse models, opioids like morphine and oxycodone were administered in conjunction with JZL184, a pharmacological inhibitor of the monoacylglycerol lipase (MAGL). MAGL is an enzyme that breaks down 2-arachidonoylglycerol, an endocannabinoid that activates CB1 receptors in the brain and nervous system which modulates pain and triggers reward pathways in a similar way to opioids. The results of the study found that JZL184 administration attenuated the rewarding effects of opioids but not its analgesic effects [98]. Thus, it was concluded that enhancing endocannabinoid signaling could modulate the addictive properties of opioids, providing a promising strategy for multimodal analgesia.
Precision pain management refers to the tailoring of a treatment plan based on a patient’s specific phenotype. This was described in detail by Edwards et al. [99] which included measures to phenotyping which includes use of (1) biomarkers, (2) brain imaging, (3) peripheral nerve assessment, (4) psychosocial factors, (5) sleep, (6) quantitative sensory testing, (7) endogenous pain modulation, (8) patient-reported pain qualities & characteristics. If pain specialists are able to identify specific pain phenotypes of a patient, then one could hypothetically deliver a curated pain program to optimize pain control in the future.
The past few years have already witnessed large technological improvements in the field of neuromodulation. Despite these advancements, scientists and physicians still do not completely understand the mechanisms of action at play. What is clear is that gate-control theory is rudimentary and does not explain the intricacies in which novel waveforms have improved pain management outcomes. Examples of this are new proposed mechanisms including stimulation of glial cells or stimulation of the dorsal horn (surround inhibition). Further understanding of the spinal cord and its mechanisms for pain signal transmission should allow for the further treatment advancements and improved postoperative pain management.
CONCLUSION
This narrative review of evidence presented illustrates the complexity of pain management following spine surgery. Early recognition of neurological symptoms is critical in early stages to rule-out postoperative complications. Acute postoperative pain management focuses on pharmacologics and PT. Multimodal analgesia focused on use of low dose opioids, gabapentinoids, intravenous acetaminophen provides the foundation. Use of local anesthetic infusions, EA, and/or PCA can further eliminate the dependence on opioids. Per ERAS protocol, the goal with analgesia at this stage is intended to encourage early mobilization and return to activity. PT evaluations may be initiated in the hospital but for the most part start approximately one month after surgery. This timing allows for appropriate surgical healing. PT may progress up to a recommended 12-week period, by which time, most patients are able to perform home exercise programs independently. Additional timing may be required based on the extent of spine surgery and the patient’s comorbidities. If patients do not show improvement with PT, additional time may be required (up to 12 months) to allow for neurological recovery, reverse muscle atrophy and regaining muscle proprioception. During this time, interventional procedures may be implemented to complement ongoing pharmacological treatments. If patients continue to complain of pain after 12 months, then consideration should be given to use of SCS and IT therapies. Understanding pain management options and when to deploy them is paramount to a successful postoperative pain management treatment plan. At the same time, the mechanism of action of pain is still poorly understood. Future research will allow for advanced treatments and technologies, and more optimal patient selection, lending to improved patient outcomes following spine surgery.
Notes
Conflict of Interest
David W. Lee - Consultant for Abbott, Boston Scientific, Mainstay Medical, Johnson & Johnson, Intracept. The other authors have nothing to disclose.
Funding/Support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Author Contribution
Conceptualization: CY, MYO, RM, DWL; Writing – original draft: CY, MM, OA, DWL; Writing – review & editing: CY, MM, OA, MYO, RM, DWL.