There has been little written regarding the nonoperative management of adult spinal deformity. The majority of studies are retrospective cohorts, though several prospective observational cohort studies offer more robust information. A prospective, randomized trial comparing nonoperative and operative management of adult spinal deformity is currently underway and will hopefully provide the highest quality evidence for both modalities in the management of ASD [5]. A shortcoming of many of these studies is the lack of a directed protocol for nonoperative treatments, making the benefits associated with any particular treatment difficult to ascertain.

Nonoperative management options for adult spinal deformity are numerous. They range from truly “noninvasive” techniques such as cognitive behavioral therapy, oral medications, and physical therapy to epidural steroid injections and radio-frequency ablations (Fig. 21.5). Bracing, while commonly used in adolescent idiopathic scoliosis, is not commonly used in the skeletally mature adult. The goal of nonoperative management is pain and functional improvement by reduction of pain due to instability, deformity, and neural compression. Thus, in many cases the indication for any nonoperative intervention is borrowed from lumbar degenerative disease, where degenerative flat back and stenosis with radiculopathy and claudication are common. Whether the effectiveness in treating lumbar degenerative disease translates to adult spinal deformity remains to be proven. This suspicion is confirmed by Cooper et al., who reviewed 52 patients with lumbar scoliosis treated with epidural steroid injections for management of deformity-associated radiculopathy [6]. The authors conclude that epidural steroid injections are effective; however, a successful result was obtained in only 60 % of patients at 1 week and only 37 % of patients at 1 year.

A 2007 systematic review of the literature investigating nonoperative treatment options for adult spinal deformity confirmed the paucity of evidence for these interventions [7]. There were two articles investigating bracing, three articles investigating physical therapy, two articles investigating manipulation, and one article investigating injections. Given the high prevalence of adult spinal deformity, the lack of evidence to support these seemingly common interventions is concerning. The authors conclude that activity modification and anti-inflammatory medications may be the most appropriate options and that shared decision-making and individual preferences and goals will determine which treatments are appropriate for different patients. Opioid use, not detailed in this systematic review, is becoming increasingly common [8].

The Spinal Deformity Study Group (SDSG) collected a large volume of observational data regarding the care of adult spinal deformity patients, including nonoperative treatments [9, 10]. Commonly employed nonoperative modalities included exercise/physical therapy, nonsteroidal anti-inflammatory drugs (NSAIDS), and pain management including opioids and injections. Over 70 % of the patients examined reported using some type of nonoperative technique [9]. Less symptomatic patients were not uncommonly treated with observation alone, while patients with greater symptomatic complaints were more likely to receive formal pain management referral, which included epidural steroid injections. The effectiveness of nonoperative treatments was questioned, however. The change in health-related quality of life (HRQOL) scores was compared between patients treated with observation alone versus various nonoperative treatments [10]. Over a 2-year time frame, there were no observed improvements in HRQOL for those patients utilizing nonoperative modalities. Those patients treated with observation alone improved in satisfaction alone, without improvements in pain or function. Not surprisingly, the charges associated with the nonoperative care were large, with an average of almost $10,000. The authors concluded by questioning the cost-effectiveness of nonoperative treatments, given the lack of improvement and relatively large resource utilization. This lack of improvement in HRQOL was echoed by the European Spine Study Group, who nevertheless concluded that nonoperative care may be appropriate for less symptomatic patients, thus preserving a relatively high quality of life [11]. Conversely, more symptomatic patients are less likely to improve with nonoperative care and should consider surgery more strongly.

The decision to operate in adult spinal deformity requires an informed decision-making process between the patient and surgeon, with an understanding of the expected risks and benefits of surgery. As previously noted, ASD is a heterogeneous diagnosis, with countless combinations of underlying pathologies. Perhaps the simplest division of ASD diagnoses comes with the distinction of primary and revision surgery. Within each of these subcategories, patients may present with or without evidence of neural compression (radiculopathy, myelopathy, or both), with fixed or flexible deformities, with iatrogenic, neurological, or degenerative causes of the deformity. All of these factors must be considered when assessing the possibility of success in ASD surgery. Furthermore, understanding potential results of surgery, in terms of HRQOL improvement, will allow for appropriate patient expectations and subsequent satisfaction with their surgery. There is voluminous information regarding ASD surgery in the peer-reviewed literature. We offer here a review of the outcomes of ASD surgery, with some division by the various diagnoses associated with the ASD. We would recommend that the information offered here be a “starting point” rather than a summation of the available evidence in ASD surgery.

Primary, symptomatic adult scoliosis is frequently characterized by smaller deformities in terms of coronal and sagittal plane malalignment, with subluxations and stenosis contributing to symptoms of radiculopathy and claudication. Nonoperative management has been shown useful to maintain current HRQOL measures, without reliable improvement [10, 12]. Many patients present to the surgeon having tried nonoperative management and desiring surgical intervention. Those patients choosing surgical management have been shown to have larger thoracic and lumbar Cobb measurements, more frequent leg pain, and more severe back pain [1]. These findings were consistent when participants in a dual-arm study with a randomized cohort were examined [2]. Patients electing to undergo surgery, and forgoing possible randomization into a nonoperative arm, had larger spinal deformity and greater complaints of leg and back pain. Cosmesis is also likely an important driver of the decision to have surgery, as more surgical patients report unhappiness with body image as well as concerns about progressive changes to their appearance [1]. Recognition of these drivers of surgical decision-making has important implications for the success of surgery.

Bridwell et al. studied the results of surgery for ASD and found improvements in ODI, SRS, and numerical rating scores for back and leg pain [13, 14]. Most ASD reconstructions are large surgeries and there may be a recovery period where patients do not appreciate any benefit from the surgery. It seems that true recovery takes 6–12 months, as ODI and SRS scores will continue to improve after surgery over this time frame. Beyond 1 year, however, HRQOL scores seem to plateau, and patients should not reasonably expect more improvement. As adjacent segment degeneration and pseudarthrosis are potential long-term complications of any spine fusion surgery, the durability of ASLS surgery needs to be examined as well. Bridwell et al. found that, in the absence of a complication requiring reoperation, the radiographic and clinical outcomes of adult symptomatic lumbar scoliosis surgery are durable at up to 5 years [13]. However, 10 % of patients in this cohort encountered some complication including pseudarthrosis with broken implants or junctional degeneration. In these cases, the HRQOL results were negatively affected. The negative effect of proximal junctional kyphosis (PJK) is due primarily to increasing complaints of pain, while the remainder of the SRS-22 domains may be similar to patients without this complication [15]. These findings emphasize attention to detail to minimize surgeon modifiable risk factors for complications.

The results from the SDSG have been echoed by the International Spine Study Group (ISSG) experience. Scheer et al. reported on over 400 patients with ASD and found that surgery was more effective, in general, in relieving complaints of both back and leg pain [16]. At a 2-year follow-up, nearly 70 % of operative patients reported improvements in back pain, while 25 % reported no change. Just under 50 % of operative patients reported improvements in leg pain complaints. Important to note is that nearly one third of patients complained of unchanged or worsening leg pain, and one third complained of new onset leg pain. Fortunately, improvement in back pain was associated with patient satisfaction and may be a prime driver of postoperative satisfaction. This group looked further into the deformity type, noting that patients with a pure sagittal plane deformity (Schwab type N) were the least likely to report improvements in back pain, while patients with degenerative scoliosis and coronal plane deformities were more likely to report improvements in both back and leg pain, as well as achieve clinically relevant improvements in ODI and SRS scores [17]. The importance of the deformity type, as adult deformity is a widely heterogeneous diagnosis, was emphasized by Smith et al. [18] Patients whose SVA increased over time had a concomitant decline in HRQOL scores. Similarly, those patients whose pelvic incidence-lumbar lordosis mismatch increased experienced a decline in HRQOL scores. Improvement in these radiographic parameters are associated with improvements in ODI, SF-36 Physical Component Summary score, SRS-Activity, and SRS-Pain scores (Fig. 21.6). These findings are consistent in the literature, with increasing disability (poor HRQOL) with increasing sagittal plane deformity [19]. Residual sagittal plane deformity is associated with lower HRQOL and again underscores the importance of preoperative planning in ASD.

The ISSG has also investigated the relationship between age and outcomes in patients undergoing complex ASD surgeries [20]. Patients greater than 75 years of age improved more following ASD reconstructions, including 3CO, than with nonoperative care. It is important to note, however, that not all patients achieved a minimum clinically important difference, with fewer than 50 % improving to MCID or better for ODI and 67 % of patients achieving a MCID or better change for SF-36 Physical Component Summary. O’Neill et al. did not find age to be associated with HRQOL outcomes following 3CO [21]. The only preoperative factor associated with a poor result was a history of prior spine surgeries. Complications requiring repeat reoperation were also found to negatively affect HRQOL scores, consistent with other reports. At 5 years postsurgery, SRS-22 domain scores were improved with the exception of SRS-Function, which had not improved beyond a minimum clinically important difference [22]. This fact is important for preoperative counseling, as patient expectations need to be set appropriately and a post-VCR spine may not allow many recreational activities for the sake of maintenance of correction, stability, and durability.

The ISSG cohort has reported a 17 % reoperation rate [23]. Similar to the SDSG, two common reasons for reoperation were pseudarthrosis and junctional degeneration. Not surprisingly, those patients that required revision surgery reported lower ODI and SRS-22 scores in 1 year postoperatively. The indication for reoperation may have been due to technical factors leading to worse HRQOL scores and led the authors to conclude that meticulous attention to preoperative planning, and intraoperative performance is required to optimize results (Fig. 21.7). These findings are consistent across the peer-reviewed literature. These results were echoed by Koller et al. who found a negative effect on HRQOL scores with persistent malalignment after ASD surgery [24]. Also, pseudarthrosis led to lower HRQOL scores leading the authors to emphasize the importance of preoperative planning in ASD and to identify appropriate proximal and distal fusion levels, with appropriate instrumentation. These results are in contrast to the results of Hassanzadeh et al. who found no difference between outcomes of primary versus revision ASD surgery [25]. These contrasting results emphasize the importance of patient selection in ASD, which warrants additional investigation.