Removals and Revisions of Cervical Total Disc Replacement Devices in a Consecutive Series of 1,626 Patients Beginning with the First Case Experience in 2003.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to investigate the rate of cervical total disc replacement (TDR) device removal or revision. SUMMARY OF BACKGROUND DATA: Cervical TDR has gained acceptance as an alternative to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. There have been concerns over device safety, one measure of which is subsequent surgery related to device problems. METHODS: A consecutive series of 1,626 cervical TDR patients from 2003 to June 2021 were included, consisting of TDRs up to 3 levels and hybrids (TDR and fusion). TDR removal or revision surgeries and reasons for these surgeries, procedures performed, and duration from index procedure were recorded. Data were analyzed to determine removal/revision rate and factors possibly related to these events. RESULTS: There were 24 removals/revisions (1.48%) in the 1,626 patients. Removal was performed in 23 cases (1.41%) and revision in 1 (0.06%). Among removal cases, ACDF was performed in 18 and TDR was replaced with another TDR in 5. Removals with fusion included 5 cases of osteolysis with/without C. acnes, 4 device displacement/migration, 4 posterior spinal pathology, and one for each of the following: metal allergy, approach-related complications, malpositioning, subsidence, and hypermobility. The revision involved TDR repositioning 3 days after index surgery. There were 66 patients for whom minimum of 10year follow-up was confirmed, and none had removal/revision surgery 10 or more years after index surgery. There was no relationship between occurrence of removal/revision and age, gender, body mass index, or physician experience (learning curve). The removal/revision rate was significantly higher in FDA trials vs. post-approval (4.1% vs. 1.3%, P<0.05). CONCLUSION: In this large consecutive series of patients, 1.48% of cervical TDRs were removed/revised. The low rate of removals/revisions over a long period of time provides support for the devices' safety.

New Oldowan locality Sare-Abururu (ca. 1.7 Ma) provides evidence of diverse hominin behaviors on the Homa Peninsula, Kenya.

The Homa Peninsula, in southwestern Kenya, continues to yield insights into Oldowan hominin landscape behaviors. The Late Pliocene locality of Nyayanga (∼3-2.6 Ma) preserves some of the oldest Oldowan tools. At the Early Pleistocene locality of Kanjera South (∼2 Ma) toolmakers procured a diversity of raw materials from over 10 km away and strategically reduced them in a grassland-dominated ecosystem. Here, we report findings from Sare-Abururu, a younger (∼1.7 Ma) Oldowan locality approximately 12 km southeast of Kanjera South and 18 km east of Nyayanga. Sare-Abururu has yielded 1754 artifacts in relatively undisturbed low-energy silts and sands. Stable isotopic analysis of pedogenic carbonates suggests that hominin activities were carried out in a grassland-dominated setting with similar vegetation structure as documented at Kanjera South. The composition of a nearby paleo-conglomerate indicates that high-quality stone raw materials were locally abundant. Toolmakers at Sare-Abururu produced angular fragments from quartz pebbles, representing a considerable contrast to the strategies used to reduce high quality raw materials at Kanjera South. Although lithic reduction at Sare-Abururu was technologically simple, toolmakers proficiently produced cutting edges, made few mistakes and exhibited a mastery of platform management, demonstrating that expedient technical strategies do not necessarily indicate a lack of skill or suitable raw materials. Lithic procurement and reduction patterns on the Homa Peninsula appear to reflect variation in local resource contexts rather than large-scale evolutionary changes in mobility, energy budget, or toolmaker cognition.

Is the Use of Intraoperative Neuromonitoring Justified During Lumbar Anterior Approach Surgery?

BACKGROUND: Intraoperative neuromonitoring (IONM) became widely used in spine surgery to reduce the risk of iatrogenic nerve injury. However, the proliferation of IONM has fallen into question based on effectiveness and costs, with a lack of evidence supporting its benefit for specific spine surgery procedures. The purpose of this study was to evaluate the use of IONM and the rate of neurological injury associated with anterior lumbar spinal surgery. METHODS: This was a retrospective study on a consecutive series of 359 patients undergoing lumbar anterior approach surgery for anterior lumbar interbody fusion (ALIF), total disc replacement (TDR), or hybrid (ALIF with TDR) for the treatment of symptomatic disc degeneration. Patients undergoing any posterior spine surgery were excluded. Operative notes were reviewed to identify any changes in IONM and the surgeon's response. Clinic notes were reviewed up to 3 months postoperatively for indications of iatrogenic nerve injury. RESULTS: There were 3 aberrant results with respect to IONM. Changes in IONM of a lower extremity occurred for 1 patient (0.3%). The surgeon evaluated the situation and there was no observable reason for the IONM change. Upon waking, the patient was found to have no neurological deficit. There were 2 cases of neurologic deficits in this population, which were classified as false-negatives of IONM (0.56%, 95% CI: 0.1% to 1.8%). In both cases, the patients were found to have a foot drop after the anterior approach surgery. CONCLUSION: In this study, there was 1 false-positive and 2 false-negative results of IONM. These data suggest that IONM is not beneficial in this population. However, many surgeons may feel obligated to use IONM for medicolegal reasons. There is a need for future studies to delineate cases in which IONM is beneficial and the type of monitoring to use, if any, for specific spine surgery types. CLINICAL RELEVANCE: This study questions the routine use of IONM in anterior lumbar approach surgery for the treatment of symptomatic disc degeneration. This has significant implications related to the cost of this practice.

Lumbar Total Disk Replacement Device Removals and Revisions Performed During a 20-Year Experience with 2141 Patients.

STUDY DESIGN: This was a retrospective study with prospective patient contact attempted to collect current data. OBJECTIVE: The purpose was to investigate the incidence and reasons for lumbar total disk replacement (TDR) removal or revision. SUMMARY OF BACKGROUND DATA: A concern regarding lumbar TDR was safety, particularly the need for device removal or revision. This may be particularly important considering removal/revision requires repeat anterior exposure with an increased risk of vascular injury. METHODS: Data were collected for a series of 2141 lumbar TDR patients, beginning with the first case experience in 2000. The mean follow-up was 78.6 months. For each case of device removal/revision, the reason, duration from index surgery, and procedure performed were recorded. RESULTS: Of 2141 patients, 27 (1.26%) underwent TDR removal or revision. Device removal was performed in 24 patients (1.12%), while three patients underwent revision (0.14%). Of the 24 removals, 12 were due to migration and/or loosening, three developed problems post-trauma, two developed lymphocytic reaction to device materials, two had ongoing pain, and there was one case of each: TDR was too large, vertebral body fracture (osteoporosis), lytic lesion, device subsidence and facet arthrosis, and infection seeded from a chest infection 146 months post-TDR. The three revisions were for Core repositioning (technique error), device repositioning after displacement, and core replacement due to wear/failure. With respect to timing, 37.0% of removals/revisions occurred within one-month postimplantation. Of note, 40.7% of removals/revisions occurred in the first 25 TDR cases performed by individual surgeons. There was one significant vascular complication occurring in a patient whose TDR was removed due to trauma. This was also the only patient among 258 with ≥15-year follow-up who underwent removal/revision. CONCLUSION: In this large consecutive series, 1.26% of TDRs were removed/revised. The low rate over a 20 year period supports the safety of these devices.

Expanded geographic distribution and dietary strategies of the earliest Oldowan hominins and Paranthropus.

The oldest Oldowan tool sites, from around 2.6 million years ago, have previously been confined to Ethiopia's Afar Triangle. We describe sites at Nyayanga, Kenya, dated to 3.032 to 2.581 million years ago and expand this distribution by over 1300 kilometers. Furthermore, we found two hippopotamid butchery sites associated with mosaic vegetation and a C4 grazer-dominated fauna. Tool flaking proficiency was comparable with that of younger Oldowan assemblages, but pounding activities were more common. Tool use-wear and bone damage indicate plant and animal tissue processing. Paranthropus sp. teeth, the first from southwestern Kenya, possessed carbon isotopic values indicative of a diet rich in C4 foods. We argue that the earliest Oldowan was more widespread than previously known, used to process diverse foods including megafauna, and associated with Paranthropus from its onset.

Impact of previous lumbar spine surgery on the outcome of lumbar total disc replacement: analysis of prospective 5-year follow-up study data.

PURPOSE: It is sometimes anticipated that patients with prior spine surgery will have a compromised outcome from future procedures. The purpose of this study was to compare TDR outcomes in patients with prior lumbar spine surgery to those with no previous surgery. METHODS: Post hoc analysis was performed on 5-year follow-up data collected prospectively in the multi-centre FDA-regulated trial for the activL® Artificial Disc which involved 376 patients treated for single-level symptomatic disc degeneration. Clinical outcome measures included the Oswestry Disability Index (ODI), visual analog scales (VAS) assessing back and leg pain, SF-36, adverse events, and re-operations. Radiographic outcomes included flexion/extension range of motion (ROM) and translation of the operated segment. Patients were divided into two groups: Prior Lumbar Surgery (PLS, n = 92) and No Prior Lumbar Surgery (NPLS, n = 284). RESULTS: Baseline demographics were similar in the two groups. ODI, VAS, and SF-36 Physical Component Scale scores improved significantly (p < 0.05) from baseline in both groups with improvements maintained through 5-year post-TDR with no significant differences between groups. There were no statistically significant differences in rates of serious device-related events, procedure-related events, or re-operations. While ROM was significantly less prior to TDR surgery in the PLS group, there was no significant difference in ROM at post-operative points. CONCLUSION: Prior lumbar spine surgery was not associated with compromised outcomes following TDR. These results are in line with reports from earlier studies with shorter follow-up, finding that non-destabilizing prior surgery is not a contra-indication for TDR provided that selection criteria are met. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Evaluation of Anterior Lumbar Interbody Fusion Performed Using a Stand-Alone, Integrated Fusion Cage.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) has been performed for many years. Often, posterior supplemental fixation has been used to provide additional stability to the operated segment. Interbody implants have evolved to incorporate unique designs, polyetheretherketone, integrated screws, and surface texture. With these changes, the need for supplemental posterior fixation has been debated. The purpose of this study was to evaluate the clinical outcome of stand-alone ALIF. METHODS: A surgery log was reviewed to identify the consecutive series of 58 patients undergoing ALIF using a STALIF stand-alone cage from March 2011 (first case) to December 2018 (minimum 24 months postoperative) with a mean follow-up of 30.6 months. All patients were treated for symptomatic degenerative conditions. Charts were reviewed to collect general patient information, operative data, and patient-reported outcomes, including the Oswestry Disability Index (ODI), visual analog scales (VAS) separately assessing back pain and leg pain, and re-operations. For patients who were not seen recently in clinic for follow-up, current outcome data were collected through mailings. RESULTS: The mean operative blood loss was 52.1 mL. There was a statistically significant improvement in mean ODI scores from 41.7 preoperatively to 21.0 at follow-up (P < 0.01). There was also significant improvement (P < 0.01) in VAS back pain (6.0-2.5) and leg pain (4.1-1.3). Subsequent surgery was performed on 9 patients. Reasons for re-operation were pseudoarthrosis (n = 3), progressive cage subsidence (n = 1), foraminal stenosis at the index level (n = 1), metal allergy reaction (n = 2), adjacent segment degeneration (n = 1), and ongoing pain (n = 1). There were no cases of device failure, vertebral body fracture, or screws backing out of the implant. DISCUSSION: Stand-alone ALIF was associated with statistically significant improvements in ODI scores, back pain, and leg pain. The re-operation rate for clear pseudoarthrosis or cage subsidence was 6.8%. These results support that stand-alone ALIF produces good outcomes in patients treated for symptomatic disc degeneration while avoiding the use of posterior fixation and its complication risk and cost. CLINICAL RELEVANCE: The results of this study support that stand-alone ALIF is a viable procedure for the treatment of symptomatic disc degeneration unresponsive in patients who have failed nonoperative care and who do not have specific indications for supplemental posterior instrumentation.

In which cases do surgeons specializing in total disc replacement perform fusion in patients with symptomatic lumbar disc degeneration?

PURPOSE: The purpose of this study was to investigate reasons and their frequency for why spine surgeons subspecializing in total disc replacement (TDR) performed lumbar fusion rather than TDR. METHODS: The study was based on a consecutive series of 515 patients undergoing lumbar TDR or fusion during a 5-year period by three surgeons specializing in TDR. For each fusion patient, the reason for not performing TDR was recorded. RESULTS: TDR was performed in 65.4% (n = 337) of patients and the remaining 34.6% (n = 178) underwent anterior lumbar interbody fusion (ALIF ± posterior instrumentation). Of the 178 fusion patients, the most common reason for fusion was combined factors related to severe degenerative changes (n = 59, 11.5% of the study population). The second most common reason was > Grade 1 spondylolisthesis (n = 32, 6.2%), followed by insurance non-coverage (n = 24, 4.7%), and osteopenia/osteoporosis (n = 13, 2.5%). Fusion patients were significantly older than TDR patients (52.5 vs. 41.6 years; p < 0.01). There was no significant difference with respect to gender (41.2% female vs. 43.8% female, p > 0.05) or the percentage of patients with single-level surgery (61.2% vs. 56.7%, p > 0.05). CONCLUSION: The most common reason for not performing lumbar TDR was related to anatomic factors that may compromise stability of the operated segment and/or TDR functionality. The older age of fusion patients may be related to these factors. This study found that many patients are appropriate candidates for lumbar TDR. However, even among TDR subspecialists, fusion is preferred when there are factors that cannot be addressed with TDR and/or may compromise implant functionality.

Appropriate Telemedicine Utilization in Spine Surgery: Results From a Delphi Study.

STUDY DESIGN: Delphi expert panel consensus. OBJECTIVE: To obtain expert consensus on best practices for appropriate telemedicine utilization in spine surgery. SUMMARY OF BACKGROUND DATA: Several studies have shown high patient satisfaction associated with telemedicine during the COVID-19 peak pandemic period as well as after easing of restrictions. As this technology will most likely continue to be employed, there is a need to define appropriate utilization. METHODS: An expert panel consisting of 27 spine surgeons from various countries was assembled in February 2021. A two-round consensus-based Delphi method was used to generate consensus statements on various aspects of telemedicine (separated as video visits or audio visits) including themes, such as patient location and impact of patient diagnosis, on assessment of new patients. Topics with ≥75% agreement were categorized as having achieved a consensus. RESULTS: The expert panel reviewed a total of 59 statements. Of these, 32 achieved consensus. The panel had consensus that video visits could be utilized regardless of patient location and that video visits are appropriate for evaluating as well as indicating for surgery multiple common spine pathologies, such as lumbar stenosis, lumbar radiculopathy, and cervical radiculopathy. Finally, the panel had consensus that video visits could be appropriate for a variety of visit types including early, midterm, longer term postoperative follow-up, follow-up for imaging review, and follow-up after an intervention (i.e., physical therapy, injection). CONCLUSION: Although telemedicine was initially introduced out of necessity, this technology most likely will remain due to evidence of high patient satisfaction and significant cost savings. This study was able to provide a framework for appropriate telemedicine utilization in spine surgery from a panel of experts. However, several questions remain for future research, such as whether or not an in-person consultation is necessary prior to surgery and which physical exam maneuvers are appropriate for telemedicine.Level of Evidence: 4.

Prospective, multicenter clinical trial comparing M6-C compressible six degrees of freedom cervical disc with anterior cervical discectomy and fusion for the treatment of single-level degenerative cervical radiculopathy: 2-year results of an FDA investigational device exemption study.

BACKGROUND CONTEXT: Various designs of total disc replacement (TDR) devices have been compared to anterior cervical discectomy and fusion (ACDF) with favorable outcomes in FDA-approved investigational device exemption trials. The design of M6-C with a compressible viscoelastic nuclear core and an annular structure is substantially different than prior designs and has previously demonstrated favorable kinematics and clinical outcomes in small case series. PURPOSE: To evaluate the safety and effectiveness of the novel M6-C compressible artificial cervical disc compared with ACDF for subjects with single-level degenerative cervical radiculopathy. STUDY DESIGN/SETTING: Prospective, multicenter, concurrently and historically controlled, FDA-approved investigational device exemption clinical trial. PATIENT SAMPLE: Subjects with one-level symptomatic degenerative cervical radiculopathy were enrolled and assigned to receive M6-C or ACDF. OUTCOME MEASURES: Pain and function (Neck Disability Index, VAS), quality of life (SF-36), safety, neurologic, and radiographic assessments of motion (both flexion extension and lateral bending) were performed. The primary clinical endpoint was composite clinical success (CCS) at 24 months. METHODS: Using propensity score subclassification to control for selection bias, 160 M6-C subjects were compared to a matched subset of 189 ACDF controls (46 concurrent and 143 historical controls). RESULTS: Both ACDF and M6-C subjects reported significant improvements in patient-reported outcomes at all time points over baseline. Overall SF-36 Physical Component Score and neck and arm pain scores were significantly improved for M6-C as compared to ACDF treatment. CCS and mean Neck Disability Index improvements were similar between M6-C and ACDF. Correspondingly, there were significantly fewer subjects that utilized pain medication or opioids following M6-C treatment at 24 months relative to baseline. Range of motion was maintained in subjects treated with M6-C. Subsequent surgical interventions, dysphagia rates, and serious adverse events were comparable between groups. CONCLUSIONS: M6-C treatment demonstrated both safety and effectiveness for the treatment of degenerative cervical radiculopathy. Treatment with M6-C demonstrated noninferiority for the primary endpoint, indicating a similar ability to achieve CCS at 24 months. However, for the secondary endpoints, M6-C subjects demonstrated significantly improved pain and function compared to ACDF subjects, while maintaining range of motion, improving quality of life, and decreasing analgesic and opioid usage at 2 years postoperatively relative to baseline.

Analysis of re-operations after cervical total disc replacement in a consecutive series of 535 patients receiving the ProDisc-C device.

INTRODUCTION: One important factor in evaluating the safety of an implant is the rate of subsequent surgery and the reasons for surgery, particularly those that are related to possible problems with the implant. The purpose of this study was to determine the overall re-operation rate (including revisions, removals, device-related, procedure-related, adjacent segment, and others) for a large consecutive series of cervical TDR patients beginning with the first case experience, using a single device at a single institution. METHODS: Surgery records were reviewed to identify cervical TDR patients and those who underwent subsequent surgery. Cervical TDR cases involving ProDisc-C were identified, beginning with the first case performed in 2003 at a multisite spine specialty centre. Only patients who were at least 2 years post-operative were included, producing a consecutive series of 535 patients. There were 115 hybrids in the series (TDR at one level and fusion at an adjacent segment). Data collected included general demographics and level(s) operated. A surgery log through 12-31-18 was reviewed to identify re-operations occurring in the TDR patients. For each re-operation, the reason, duration from index surgery, and procedure were recorded. The mean duration from the index surgery to the search of the surgery log for re-operations was 78.3 months, range 24 to 181 months. RESULTS: Re-operation occurred in 30 patients (5.6%). These included: 3 TDR removals and revision to anterior discectomy and fusion (1 for migration, 1 for subsidence, and 1 for spondylosis), 1 TDR repositioning, 21 secondary surgeries for adjacent segment degeneration (5 of which were adjacent to fusion levels in hybrid procedures), 1 wound infection, 1 hematoma, and 2 received stimulators for pain control. There were no re- operations for device failure. In cases of re-operation for adjacent segment degeneration, the mean duration between the index surgery and re-operation was 47.3 months. CONCLUSION: The re-operation rate was 5.6%. No surgeries were performed for device failure. These results support the safety of the TDR device.

In which cases do surgeons specializing in total disc replacement perform fusion in patients with cervical spine symptoms?

PURPOSE: The purpose was to investigate reasons and their frequency for why total disc replacement (TDR) specialty surgeons performed anterior cervical discectomy and fusion (ACDF) rather than TDR. METHODS: A consecutive series of 464 patients undergoing cervical spine surgery during a 5-year period by three TDR specialty surgeons was reviewed. For each ACDF, the reason for not performing TDR was recorded. RESULTS: TDR was performed in 76.7% of patients (n = 356) and ACDF in 23.3% (n = 108). The most common reason for ACDF versus TDR was anatomical (conditions that may not be adequately addressed with TDR and/or may interfere with device function), which occurred in 64 of 464 patients (13.79%). The second most common reason was insurance (denial/lack of coverage n = 17, 3.23%), and deformity/kyphosis not addressable with TDR was noted in 13 (2.80%). Pseudoarthrosis repair led to ACDF in three patients (0.65%), two did not receive TDR due to osteoporosis (0.43%), and in two others (0.43%) ACDF was undertaken due to high risk of heterotopic ossification. There was one case (0.22%) each of: nickel allergy, trauma with posterior element fracture, TDR removal, multiple prior cervical spine surgeries, concern about artifact on future imaging studies, benign osteoblastic bone, and limitation to adequate surgical approach for TDR. ACDF patients' mean age was significantly greater than TDR patients' (55.3 vs. 46.7 years; p < 0.01). TDR group had significantly more single-level procedures than ACDF (60.8% vs. 43.5%; p < 0.05). CONCLUSION: The most common reason for ACDF versus TDR was anatomy that may compromise segmental stability and/or TDR functionality. Older age and greater number of operated levels may be related to anatomical factors, primarily significant osteophytes and severely degenerated facets. These factors, as well as deformity/kyphosis, are more common in older patients and require multi-level treatment. This study found that many patients are good cervical TDR candidates; however, even among TDR specialists, ACDF may be preferred where it is prudent to not take undue risks. These slides can be retrieved under Electronic Supplementary Material.

Diets of mammalian fossil fauna from Kanapoi, northwestern Kenya.

Carbon isotope ratios of mammalian teeth from the Kanapoi site in northern Kenya are interpreted in the context of C3 and C4 derived resources to investigate the paleoecology of Australopithecus anamensis. δ13C values of large mammals, when compared at the taxon level, show an ecosystem that is strongly biased towards mixed feeders and browsers. However, sufficient C4 resources were present such that some C4 dominated grazers were also present in the large mammal fauna. Analyses of micromammals shows that their diets were C3 dominated or C3-C4 mixed. Carbon isotope studies of primates shows that the major primate tribes-Colobini, Papioini, Hominini-all made some use of C4 resources in their respective diets; the Hominini had a higher fraction of C3 diet resources than the other primate tribes represented in the fossil record.

Postoperative Care Pathways Following Lumbar Total Disc Replacement: Results of a Modified Delphi Approach.

STUDY DESIGN: A modified Delphi method was used to establish consensus. Subject matter experts were invited to participate as the expert panel. Best practice statements were distributed to the panel. Panel members were asked to mark "agree" or "disagree" after a series of statements during several rounds until either consensus could be obtained or the practice method was deemed unable to achieve consensus. OBJECTIVE: Lumbar total disc replacement (TDR) is acknowledged as an alternative to spinal fusion in appropriately selected patients. There is a lack of unanimity on the appropriate postoperative patient protocols and rehabilitation expectations for the procedure. The long-term viability of Lumbar TDR, further adoption in the community setting and specific patient outcomes are contingent on the existence of appropriate postoperative recovery programs. SUMMARY OF BACKGROUND DATA: Currently there are no established methods for postoperative care following lumbar TDR. Establishing a postoperative clinical pathway algorithm may improve patient outcomes with respect to lumbar TDR. METHOD: A lumbar TDR expert panel of 22 spine surgeons employed a modified Delphi method to drive consensus on postoperative care following single-level Lumbar TDR. The panel first reviewed literature and guidelines relevant to postoperative care following lumbar TDR. Panel members considered 21 survey questions intended to determine "standard-practice" postoperative care recommendations for patients who have undergone lumbar TDR for the initial recovery phase (0-4 wk) and rehabilitation (4-20 wk). Each panel member participated in a round of anonymous voting followed by a group discussion. Consensus was defined as 80% agreement or higher among the respondents. RESULTS: Consensus was achieved in 11 of the 21 survey questions. There was a high degree of consensus around the key goals for both the initial recovery and rehabilitation phases, ceased use of narcotics for pain management by 4 weeks postoperative, unrestricted walking immediately following surgery, timelines for physical therapy (within 2-4 wk) and return to work based on level of activity (as early as 1 wk postoperative). Lack of agreement included the use of back bracing and timing of postoperative visits. Generally, panel members felt that patient expectations regarding return to function were different following lumbar TDR versus fusion and warrant further study. CONCLUSION: Surgeon and patient alignment around postoperative expectations may significantly affect the long-term results of lumbar TDR. This surgeon consensus study found agreement for immediate postoperative ambulation, rapid reduction in opioids within the first month, and early return to work. When expectations are appropriately set with patients preoperatively, both provider and patient have shared goals in the return-to-function process. LEVEL OF EVIDENCE: 5.