Removal of Spinal Instrumentation Is Not Required to Successfully Treat Postoperative Wound Infections in Most Cases.

INTRODUCTION: Controversy exists regarding whether spinal implants need to be removed to treat postoperative deep wound infections (DWIs). This retrospective study aimed to determine whether the removal or retention of implants impacts the successful treatment of a DWI after spine surgery. METHODS: Postoperative spine surgery patients presenting with signs of infection who underwent irrigation and debridement (I&D) at Twin Cities Spine Surgeons at Abbott Northwestern Hospital, Minnesota, USA, were studied. First, the persistence of infection when implants were retained or removed was assessed. Second, we analyzed the persistence of infection with respect to the number of I&D, the use of vacuum-assisted closure (VAC) treatment, pseudoarthrosis status, and functional outcomes. RESULTS: One hundred thirty-five patients were included. Treatment of infection with retention of implants occurred in 64% (87/135); of these, 7% (6/87) had a persistent infection. Of patients with implant removal (36%, 48/135), 6% (3/48) had a persistent infection. Thus, we observed no difference between treatment with implants present compared to implants removed (p = 1.0). Fifty of the 135 patients (37%) received I&D and primary wound closure, and 85 (63%) patients received I&D and VAC treatment. There was no statistical difference between primary wound closure and VAC treatment (p = 0.15) with respect to persistence. Repeat I&D with VAC (three or more times) had a significantly lower rate of recurrence than those with two I&Ds. Pseudoarthrosis and persistent infection were unrelated. At minimum one-year follow-up, achieving a minimum clinically important difference in functional outcome was independent of persistent infection status. CONCLUSION: Persistent infection was unrelated to the retention of implants. When VAC treatment was deemed necessary, more than two I&Ds resulted in a significantly better cure for infection. Those with a persistent infection were no more likely to exhibit pseudoarthrosis than those with no persistent infection. All patients showed improvement in functional outcomes at minimum one-year follow-up.

Choose Wisely: Surgical Selection of Candidates for Outpatient Anterior Cervical Surgery Based on Early Complications Among Inpatients.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are attractive targets for transition to the outpatient setting. We assessed the prevalence of rapid responses and major complications in the inpatient setting following 1 or 2-level ACDFs and CDAs. We evaluated factors that may place patients at greater risk for a rapid response or a postoperative complication. METHODS: This was an institutional review board-approved, retrospective cohort study of adults undergoing 1 or 2-level ACDF or CDA at 1 hospital over a 2-year period (2018 and 2019). Data on patient demographic characteristics, surgical procedures, and comorbidities were collected. Rapid response events were identified by hospital floor staff and involved acute changes in a patient's clinical condition. Complications were events that were life-threatening, required an intervention, or led to delayed hospital discharge. RESULTS: In this study, 1,040 patients were included: 888 underwent ACDF and 152 underwent CDA. Thirty-six patients (3.5%) experienced a rapid response event; 22% occurred >24 hours after extubation. Patients having a rapid response event had a significantly higher risk of developing a complication (risk ratio, 10; p < 0.01) and had a significantly longer hospital stay. Twenty-four patients (2.3%) experienced acute complications; 71% occurred >6 hours after extubation. Patients with a complication were older and more likely to be current or former smokers, have chronic obstructive pulmonary disease, have asthma, and have an American Society of Anesthesiologists (ASA) score of >2. The length of the surgical procedure was significantly longer in patients who developed a complication. All patients who developed dysphagia had a surgical procedure involving C4-C5 or more cephalad. Patients with a rapid response event or complication were more commonly undergoing revision surgical procedures. CONCLUSIONS: Rapid response and complications are uncommon following 1 or 2-level ACDFs or CDAs but portend a longer hospital stay and increased morbidity. Revision surgical procedures place patients at higher risk for rapid responses and complications. Additionally, older patients, patients with chronic obstructive pulmonary disease or asthma, patients who are current or former smokers, and patients who have an ASA score of ≥3 are at increased risk for postoperative complications. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Treatment of degenerative spondylolisthesis by instrumented posterolateral versus instrumented posterolateral with transforaminal lumbar interbody single-level fusion.

BACKGROUND: The purpose of this study was to compare outcomes of patients with degenerative spondylolisthesis treated by posterolateral lumbar fusion (PLF) versus PLF with transforaminal lumbar interbody fusion (PLF + TLIF). Studies of PLF versus PLF + TLIF have shown either equivalence or support for PLF + TLIF in lumbar spine surgery. Many are heterogeneous in the conditions treated, with few considering only spondylolisthesis of degenerative origin. Radiographic outcomes tend to favor PLF + TLIF, but this has not translated into better clinical outcomes. METHODS: This was a retrospective cohort study. Forty-nine patients undergoing single-level PLF and seventy patients undergoing single-level PLF + TLIF with two-year follow-up were retrospectively reviewed. Demographics, Oswestry Disability Index (ODI), implant cost, surgical data, and complications were analyzed. RESULTS: There was no difference in ODI improvement at two-year follow-up between the cohorts (P=0.97). Dural tears were more common in the PLF cohort (P<0.01), but otherwise complication and reoperation rates were similar. Implant cost (P<0.01) and operative time (P=0.01) were higher in the PLF + TLIF cohort. CONCLUSIONS: The addition of a TLIF to a PLF did not result in a functional improvement in the treatment of degenerative spondylolisthesis as measured by the ODI.

Interleukin-8 as a therapeutic target for chronic low back pain: Upregulation in human cerebrospinal fluid and pre-clinical validation with chronic reparixin in the SPARC-null mouse model.

BACKGROUND: Low back pain (LBP) is the leading global cause of disability and is associated with intervertebral disc degeneration (DD) in some individuals. However, many adults have DD without LBP. Understanding why DD is painful in some and not others may unmask novel therapies for chronic LBP. The objectives of this study were to a) identify factors in human cerebrospinal fluid (CSF) associated with chronic LBP and b) examine their therapeutic utility in a proof-of-concept pre-clinical study. METHODS: Pain-free human subjects without DD, pain-free human subjects with DD, and patients with chronic LBP linked to DD were recruited and lumbar MRIs, pain and disability levels were obtained. CSF was collected and analyzed by multiplex cytokine assay. Interleukin-8 (IL-8) expression was confirmed by ELISA in CSF and in intervertebral discs. The SPARC-null mouse model of progressive, age-dependent DD and chronic LBP was used for pre-clinical validation. Male SPARC-null and control mice received systemic Reparixin, a CXCR1/2 (receptors for IL-8 and murine analogues) inhibitor, for 8 weeks. Behavioral signs of axial discomfort and radiating pain were assessed. Following completion of the study, discs were excised and cultured, and conditioned media was evaluated with a protein array. FINDINGS: IL-8 was elevated in CSF of chronic LBP patients with DD compared to pain-free subjects with or without DD. Chronic inhibition with reparixin alleviated low back pain behaviors and attenuated disc inflammation in SPARC-null mice. INTERPRETATION: These studies suggest that the IL-8 signaling pathway is a viable therapy for chronic LBP. FUND: Supported by NIH, MMF, CIHR and FRQS.

Posterolateral Versus Transforaminal Interbody L4/5 Fusion: Correlation With Subsequent Surgery.

STUDY DESIGN: This is a retrospective cohort study. OBJECTIVE: To compare posterolateral versus transforaminal interbody fusion (PLF vs. PLF+TLIF) of the L4/5 segment regarding rates of subsequent surgery, clinical and radiographic parameters, and patient satisfaction. SUMMARY OF BACKGROUND DATA: Surgical treatment of lumbar stenosis, decompression with or without fusion, is an efficacious treatment in select patients. Reoperation is thought to be a problem after lumbar fusion. Despite multiple studies, the fusion method that minimizes the need for subsequent surgery has yet to be determined. MATERIALS AND METHODS: A retrospective cohort study was conducted on 89 patients who had an isolated L4/5 decompression and fusion, from January 2006 to 2012. All patients had stenosis and degenerative spondylolisthesis at the L4/5 level. All surgeries were performed at a single center, using either PLF (31 patients) or PLF+TLIF (58 patients) techniques. Preoperative and postoperative patient-reported outcome measures (Oswestry disability index, visual analog scale back pain, visual analog scale leg pain) and radiographic parameters (L4/5 lordosis and overall lumbar lordosis) were measured. Patient satisfaction was acquired via a questionnaire. Chart reviews and patient questionnaires were used to determine the incidence of subsequent lumbar surgery over a minimum follow-up of 5 years. RESULTS: At an average of 8.7 years follow-up, 2 of 31 patients in the PLF group had subsequent lumbar surgery, compared with 16 of 58 patients in the PLF+TLIF group (6% vs. 28%; P=0.02). There were no significant differences between groups with respect to sex, age, body mass index, tobacco, perioperative measures, patient-reported outcomes, or radiographic parameters (P>0.05). CONCLUSIONS: Both PLF and PLF+TLIF are effective fusion methods for L4/5 stenosis and spondylolisthesis. In this study, patients treated with PLF were less likely to undergo a subsequent lumbar surgery. More research is needed to determine which factors influence whether PLF or PLF+TLIF should be used in these patients. LEVEL OF EVIDENCE: Level III.

Evidence for a Role of Nerve Injury in Painful Intervertebral Disc Degeneration: A Cross-Sectional Proteomic Analysis of Human Cerebrospinal Fluid.

Intervertebral disc degeneration (DD) is a cause of low back pain (LBP) in some individuals. However, although >30% of adults have DD, LBP only develops in a subset of individuals. To gain insight into the mechanisms underlying nonpainful versus painful DD, human cerebrospinal fluid (CSF) was examined using differential expression shotgun proteomic techniques comparing healthy control participants, subjects with nonpainful DD, and patients with painful DD scheduled for spinal fusion surgery. Eighty-eight proteins were detected, 27 of which were differentially expressed. Proteins associated with DD tended to be related to inflammation (eg, cystatin C) regardless of pain status. In contrast, most differentially expressed proteins in DD-associated chronic LBP patients were linked to nerve injury (eg, hemopexin). Cystatin C and hemopexin were selected for further examination using enzyme-linked immunosorbent assay in a larger cohort. While cystatin C correlated with DD severity but not pain or disability, hemopexin correlated with pain intensity, physical disability, and DD severity. This study shows that CSF can be used to study mechanisms underlying painful DD in humans, and suggests that while painful DD is associated with nerve injury, inflammation itself is not sufficient to develop LBP. PERSPECTIVE: CSF was examined for differential protein expression in healthy control participants, pain-free adults with asymptomatic intervertebral DD, and LBP patients with painful intervertebral DD. While DD was related to inflammation regardless of pain status, painful degeneration was associated with markers linked to nerve injury.

Radiculopathy in degenerative lumbar scoliosis: correlation of stenosis with relief from selective nerve root steroid injections.

OBJECTIVE: The purpose is to define the origin of radiculopathy of patients with degenerative lumbar scoliosis-stenosis and to assess the correlation between percentage of initial radicular leg pain relief with selective nerve root injections and lateral canal dimensions. DESIGN: Retrospective clinical study. SETTING AND PATIENTS: Thirty-six consecutive patients (average age 72) from Twin Cities Spine Center with degenerative lumbar scoliosis (average major curve 25°) and radicular symptoms were studied. INTERVENTIONS: Patients underwent 46 selective steroid injections of nerve roots concordant with clinical symptomatology. OUTCOME MEASURES: Radiographic measurements included major and lumbosacral curve Cobb angle. Computerized measurements of magnetic resonance imaging (MRI) included minimum subarticular height and foramen cross-sectional area of the nerve roots that were injected. Initial response from the nerve root injections was also rated. RESULTS: Twenty-five percent of nerve root symptoms were coming from the major curve, 72.2% from the lumbosacral hemicurve and 2.8% from both (P<0.001). The affected nerve roots were more frequently the L4 (34.8%) and L5 (28.3%) nerve roots. A total of 71.7% of radicular symptoms were originating from the concavity of the curve and 28.7% from the convexity (P<0.001). The relief from injections was more than 50% in 75% of the patients at 15 days postinjection. There was no statistical significant correlation (P>0.05) between the lateral canal dimensions and the initial response to injection of anesthetic plus steroid injection. CONCLUSIONS: In degenerative lumbar scoliotic curves, radicular symptoms are attributed mainly to nerve roots exiting from the concavity of the lumbosacral hemicurve. No evidence was found that the rate of initial relief from selective nerve root injections correlates with the degree of stenosis noted in the MRI.

Functional and radiological outcomes of 360 degrees fusion of three or more motion levels in the lumbar spine for degenerative disc disease.

STUDY DESIGN: This is a single-center, multisurgeon, retrospective study of radiologic and functional outcome measures at a minimum 2-year follow-up. OBJECTIVE: We studied the radiologic and functional outcomes following 3 or more motion segment fusions of the lumbar spine for low back pain due to multilevel degenerative disc disease. SUMMARY OF BACKGROUND DATA: Good functional outcomes have been reported for 1 or 2-level fusions, but there are no reports dealing specifically with 3 or more level fusions. METHODS: A total of 80 adult patients met the inclusion/exclusion criteria of multilevel (3 or more motion segments) 360 degrees fusion for lumbar degenerative disc disease, failed nonoperative treatment for at least 1 year, no previous lumbar fusion, no fracture, tumor or infection of the spine, completed preoperative and postoperative functional questionnaires including SF-36 (n = 80), Oswestry (n = 69), Roland Morris (n = 68), and radiologic evaluation of fusion solidity with a minimum follow-up of 2 years. RESULTS: The average patient age was 57 years (range, 27-81). The mean follow-up was 4 years (2-7). On average, patients had fusion of 4 motion segments (range, 3-8 levels). Solid arthrodesis at the first surgery was achieved in 65/80 (81%). Adjacent segment degeneration was noted in 11 patients. Of these, 5 had undergone an extension of their fusion within the study period. There were no deaths or neurologic complications. Deep wound infection occurred in 2 patients, neither requiring implant removal. The Oswestry Disability Index scores improved from 49.8 to 35.1 (29.5%) (P < 0.001). The Roland Morris scores improved from 17.6 to 12.2 (30.7%) (P < 0.001). For the SF-36 scales, significant (P < 0.001) improvement was seen in all scales except Role Emotional scores and Mental Composite Scales. CONCLUSION: The surgical treatment of lumbar degenerative disc disease by 360 degrees fusion should be considered for properly selected patients. The goal of surgery is reduction, not elimination of disability.

Perioperative complications in revision anterior lumbar spine surgery: incidence and risk factors.

STUDY DESIGN: This is a retrospective review of 129 consecutive anterior lumbar revision surgeries in 108 patients. It is a single-center, multi-surgeon study. OBJECTIVE: To determine occurrence rates and risk factors for perioperative complications in revision anterior lumbar fusion surgery. SUMMARY OF BACKGROUND DATA: Although complication rates from large series of primary anterior fusion procedures have been reported, reports of complication rates for revision anterior fusion procedures are relatively rare. Concern exists chiefly about the risk to vascular and visceral structures because of scar tissue formation from the original anterior exposure. METHODS: This was a retrospective review of 129 consecutive anterior revision lumbar surgeries in 108 patients operated between 1998 and 2003. There were 40 men and 68 women. The age of patients ranged from 25 to 83 (average 50.6 years). Patients were excluded if surgery was for tumor or infection. Patients were divided into 2 groups; those with revision surgery at the same level and those with revision surgery at an adjacent level. Outcome measures included all perioperative complications. Statistical analysis included Student t test and nonparametric sign-rank. RESULTS: The number of surgical levels treated for revision was similar between the 2 groups (1 level 69%; 2 levels 19%; 3 or more levels 12%). Revision cases at the same operative level had a higher overall complication rate (42%) compared with extensions (20%; P = 0.007). This difference was primarily because of vein lacerations (23.7% vs. 3.6%, P = 0.002). There were 2 ureteral problems, both successfully salvaged. There were no arterial injuries or deaths. CONCLUSION: Complication rates for revision lumbar surgery in this series were 3 to 5 times higher than reported for primary lumbar exposures. Complication rates were significantly higher for revision anterior lumbar fusions at the same segment, which were typically in the lower lumbar spine, compared with cases involving extensions, which were typically in the upper lumbar spine.

Revision lumbar arthrodesis for the treatment of lumbar cage pseudoarthrosis: complications.

STUDY DESIGN: A study documenting major complications encountered in revision procedures for lumbar cage pseudoarthrosis. OBJECTIVE: To document the perioperative complications associated with revision surgery for threaded cylindrical cage pseudoarthrosis. SUMMARY OF BACKGROUND DATA: Pseudoarthrosis after cylindrical cage placement manifests as persistent or recurrent pain and disability after surgery. Revision strategies include isolated posterior stabilization and posterior bone grafting, versus circumferential revision where an attempt is made to remove the cages anteriorly, followed by posterior stabilization and fusion. Potential complications associated with these revision procedures have not been adequately documented in the past. METHODS: Forty-seven consecutive patients with the diagnosis of cylindrical cage pseudoarthrosis were surgically treated with either a circumferential revision (AP) or an isolated posterior instrumented fusion (P). All intraoperative and postoperative complications were documented. Radiographic interbody fusion rates and preoperative and postoperative visual analog scale (VAS) scores were documented. RESULTS: Three of the AP patients, all with anterior cage placement at L5-S1, had iliac vein lacerations requiring repair. A fourth patient had a ureteral injury requiring subsequent nephrectomy. Three patients who underwent circumferential revision and 2 patients who had an isolated posterior procedure had postoperative complications, including 2 infections (1 AP and 1 P), 1 radiculopathy (P), and 2 patients with prolonged ileus (both AP). There was a statistically significant decrease in overall VAS scores postoperatively for the 2 groups using the paired t test (P<0.0001). There was no difference in either the preoperative (P=0.22) or 2-year postoperative (P=0.30) VAS scores between the AP and P groups [rank-sum (Mann-Whitney) t tests]. Interbody fusion was achieved in 79% (30 of 38 levels) in the AP group. The interbody fusion rate was 37% (8 of 22) for the P group. CONCLUSIONS: Circumferential revision including cage removal, structural allograft placement, and posterior stabilization is associated with increased perioperative complications. Although an anterior approach showed increased interbody fusion rates, this technique did not lead to more superior clinical outcomes based on VAS scores. It remains to be shown by larger prospective studies if there is a true difference in outcome between these 2 groups that will justify the increased perioperative morbidity associated with attempted cage removal.

Disc space injection with marcaine as a method to evaluate painful nonunion of an interbody fusion device: a case report.

BACKGROUND CONTEXT: Discography has been successfully used to distinguish painful from asymptomatic intervertebral discs. PURPOSE: To report a case of chronic back pain following two-level interbody and posterolateral fusion in the lumbar spine that was evaluated with marcaine injection into the disc space. STUDY DESIGN: Case report. METHODS: A patient with chronic back pain after a two-level anteroposterior lumbar fusion was evaluated. A complete description of the history, physical examination, and relevant radiographic images along with a brief review of the pertinent literature are included. RESULTS: Injection of marcaine into the area of previous interbody fusion resolved the painful symptoms, and surgery confirmed the nonunion. CONCLUSIONS: In cases of interbody lumbar fusion with questionable solidity, marcain injection within the disc space can help in the assessment of the source of pain even at the intervertebral spaces with cages.

Removal of lumbar instrumentation for the treatment of recurrent low back pain in the absence of pseudarthrosis.

INTRODUCTION: Removal of spine instrumentation for the treatment of recurrent low back pain remains controversial in the absence of pseudarthrosis and when no obvious pain generators are present. It is our practice to offer these patients surgical exploration and removal of instrumentation. MATERIALS AND METHODS: Forty-five patients underwent an anterior and posterior lumbar spinal fusion. The removal of instrumentation was performed by the same surgeon and senior author of this paper (MRP). The reason for the revision surgery was recurrent low back and leg pain. All patients had a solid fusion based on a thorough surgical exploration of the fusion mass. Instrumentation was deemed either solid or loose at time of removal based on the purchase at the screw-bone interface. Final outcomes were determined using a functional and satisfactory questionnaire and compared between the two groups (Loose Instrumentation versus Solid Instrumentation). RESULTS: The majority of the patients in both groups would recommend the surgery to a family member (79% overall), would have the surgery again themselves (82%) and consider the surgery a success (77%). Pain was significantly decreased from pre-operatively to post-operatively and from pre-operative to final follow-up in both groups. The group of patients with loose instrumentation were significantly more likely to have a successful outcome than the group without loose instrumentation. CONCLUSIONS: This study indicates that the removal of instrumentation in the absence of pseudarthrosis is beneficial in the relief of low back pain and leg pain symptoms. Increased success rates were noted in patients with loose instrumentation. However, this classification was based on inter-operative inspection. Further studies of the ability to diagnose and predict success prior to surgery needs to be done.

Functional outcome analysis including preoperative and postoperative SF-36 for surgically treated adult isthmic spondylolisthesis.

STUDY DESIGN: Prospective and retrospective outcome analysis following arthrodesis for adult isthmic spondylolisthesis in 31 patients. OBJECTIVE: To examine whether or not patients having such surgery have a functional improvement in their lives. SUMMARY OF BACKGROUND DATA: The literature is full of articles concerning adolescent spondylolisthesis, the union rate for adult spondylolisthesis, the ability to reduce deformities, and the outcome of surgery for degenerative spondylolisthesis, but very scant on the postoperative functional outcome of adults with isthmic spondylolisthesis. METHODS: Functional outcome was analyzed by both preoperative and postoperative SF-36 questionnaires and by four additional functional questionnaires at follow-up. RESULTS: Statistically significant improvement was seen in six of the eight SF-36 scales. Fifty-five percent of the patients scored in the normal range at follow-up compared with none before surgery. CONCLUSION: Significant functional improvement was seen following surgical arthrodesis of the painful segments in adults with isthmic spondylolisthesis (P = 0.001). This study further confirms that such surgery is appropriate for patients failing adequate nonoperative treatment.

Degenerative disc disease treated with combined anterior and posterior arthrodesis and posterior instrumentation.

STUDY DESIGN: This study retrospectively reviewed the outcome of 58 patients all diagnosed with severe low back pain secondary to degenerative disc disease and treated with anterior arthrodesis and posterior instrumented arthrodesis. OBJECTIVES: To evaluate the outcome of a select group of patients with degenerative disc disease treated with this surgical intervention at a minimum of 2 years of follow-up. SUMMARY OF BACKGROUND DATA: Patients with degenerative disc disease who fail nonoperative treatment generally have disappointing outcomes with traditional surgical intervention. The literature analyzing posterior instrumented arthrodesis tends to exhibit the best results, but the numbers of patients with degenerative disc disease in these articles are few, and their outcomes are worse than the other low back conditions. Even patients with solid posterior arthrodesis have been noted to have continued low back pain. No articles have evaluated this specific surgical procedure in a group of patients all with the diagnosis of degenerative disc disease and no previous surgery. METHODS: All patients were diagnosed with degenerative disc disease and had failed prolonged nonoperative treatment (average 4.9 years). Fusion levels were delineated by MRI and provocative discography in correlation with history and physical examination. The senior author (M.R.P.) performed the identical operative procedure on all patients, under a single anesthetic. The arthrodesis solidity was evaluated with radiographic studies and operative posterior exploration when necessary. Final outcomes were determined using a functional and satisfaction questionnaire, return to work, narcotic use, and the rate of solid arthrodesis. Charts, radiographs, and questionnaires were reviewed by an independent evaluator at final follow-up (average 35 months). RESULTS: The solid arthrodesis rate was 95%. The three pseudoarthroses were all in patients with a three-level arthrodesis. Eighty-eight percent of the patients were able to return to work. Nineteen percent of patients required long-term narcotics, whereas 48% of the patient population were on narcotics before surgery. Eighty-six percent of the patients had a "better" rating at final follow-up. This included patients with decreased pain by visual analog scale, improved functional questionnaire, and those who would recommend the procedure to a friend or family member. Ten percent of the patients were "the same," and 3% were "worse." Lumbar lordosis was maintained or improved. Complications did not exceed literature controls. CONCLUSIONS: Selected patients with discography-proven severe low back pain secondary to degenerative disc disease, who failed extensive nonoperative treatment, were treated successfully with anterior-posterior instrumented arthrodesis. The good arthrodesis rate, return to work rate, and patient satisfaction may justify the consideration of this aggressive treatment option in this specific patient population.