The October 2024 Spine Roundup³⁶⁰ looks at: Analysis of risk factors for non-fusion of bone graft in anterior cervical discectomy and fusion: a clinical retrospective study; Does paraspinal muscle mass predict lumbar lordosis before and after decompression for degenerative spinal stenosis?; Return to work after surgery for lumbar disk herniation: a nationwide registry-based study; Can the six-minute walking test assess ambulatory function impairment in patients with cervical spondylotic myelopathy?; Complications after adult deformity surgery: losing more than sleep; Frailty limits how good we can get in adult spine deformity surgery.

Aims

Degenerative cervical spondylosis (DCS) is a common musculoskeletal disease that encompasses a wide range of progressive degenerative changes and affects all components of the cervical spine. DCS imposes very large social and economic burdens. However, its genetic basis remains elusive.

In multilevel posterior cervical instrumented fusions, extending the fusion across the cervico-thoracic junction at T1 or T2 (CTJ) has been associated with decreased rate of re-operation and pseudarthrosis but with longer surgical time and increased blood loss. The impact on patient reported outcomes (PROs) remains unclear. The primary objective was to determine whether extending the fusion through the CTJ influenced PROs at 3 and 12 months after surgery. Secondary objectives were to compare the number of patients reaching the minimally clinically important difference (MCID) for the PROs and mJOA, operative time duration, intra-operative blood loss (IOBL), length of stay (LOS), discharge disposition, adverse events (AEs), re-operation within 12 months of the surgery, and patient satisfaction. This is a retrospective analysis of prospectively collected data from a multicenter observational cohort study of patients with degenerative cervical myelopathy. Patients who underwent a posterior instrumented fusion of 4 levels of greater (between C2-T2) between January 2015 and October 2020 with 12 months follow-up were included. PROS (NDI, EQ5D, SF-12 PCS and MCS, NRS arm and neck pain) and mJOA were compared using ANCOVA, adjusted for baseline differences. Patient demographics, comorbidities and surgical details were abstracted. Percentafe of patient reaching MCID for these outcomes was compared using chi-square test. Operative duration, IOBL, AEs, re-operation, discharge disposittion, LOS and satisfaction were compared using chi-square test for categorical variables and independent samples t-tests for continuous variables. A total of 206 patients were included in this study (105 patients not crossing the CTJ and 101 crossing the CTJ). Patients who underwent a construct extending through the CTJ were more likely to be female and had worse baseline EQ5D and NDI scores (p> 0.05). When adjusted for baseline difference, there was no statistically significant difference between the two groups for the PROs and mJOA at 3 and 12 months. Surgical duration was longer (p 0.05). Satisfaction with the surgery was high in both groups but significantly different at 12 months (80% versus 72%, p= 0.042 for the group not crossing the CTJ and the group crossing the CTJ, respectively). The percentage of patients reaching MCID for the NDI score was 55% in the non-crossing group versus 69% in the group extending through the CTJ (p= 0.06). Up to 12 months after the surgery, there was no statistically significant differences in PROs between posterior construct extended to or not extended to the upper thoracic spine. The adverse event profile did not differ significantly, but longer surgical time and blood loss were associated with construct extending across the CTJ

Aims

The aim of this study was to investigate whether the type of cervical disc herniation influences the severity of symptoms at the time of presentation, and the outcome after surgical treatment.

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The aim of this study was to identify the risk factors for adverse events following the surgical correction of cervical spinal deformities in adults.

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The aim of this study was to determine how the short- and medium- to long-term outcome measures after total disc replacement (TDR) compare with those of anterior cervical discectomy and fusion (ACDF), using a systematic review and meta-analysis.

Objectives. Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine. Methods. A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion. Results. Peak anterior longitudinal ligament (ALL) strain ranged from 0.106 to 0.382 in a normal spine, and from 0.116 to 0.399 in a fused cervical spine. Strain increased from cranial to caudal levels. The mean strain increase in the motion segment immediately adjacent to the site of fusion from C2-C3 through C5-C6 was 26.1% and 50.8% following single- and two-level cervical fusion, respectively (p = 0.03, unpaired two-way t-test). Peak cervical strains following various lumbar-fusion procedures were 1.0% less than those seen in a healthy spine (p = 0.61, two-way ANOVA). Conclusion. Cervical arthrodesis increases peak ALL strain in the adjacent motion segments. C3-4 experiences greater changes in strain than C6-7. Lumbar fusion did not have a significant effect on cervical spine strain. Cite this article: H. Huang, R. W. Nightingale, A. B. C. Dang. Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study. Bone Joint Res 2018;7:28–35. DOI: 10.1302/2046-3758.71.BJR-2017-0100.R1

Objectives

The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery.

Aims

Patients seeking cervical spine surgery are thought to be increasing in age, comorbidities and functional debilitation. The changing demographics of this population may significantly impact the outcomes of their care, specifically with regards to complications. In this study, our goals were to determine the rates of functionally dependent patients undergoing elective cervical spine procedures and to assess the effect of functional dependence on 30-day morbidity and mortality using a large, validated national cohort.

Cervical total disc replacement has been in practice for years now as a viable alternative to cervical fusion in suitable cases, aspiring to preserve spinal motion and prevent adjacent segment disease. Reports are rife that neck pain emerges as an annoying feature in the early postoperative period. The facet joint appears to be the most likely source of pain. 50 patients were prospectively followed up through 5 years after having received disc replacement surgery, indicated for symptomatic soft disc herniation of the cervical spine presenting with radiculopathy. • All were skeletally mature and aged between 22 to 50. • All had failed a minimum of 6 months conservative therapy. • Up to 2 disc levels were addressed. C3 till C7 levels. • Single surgeon (first author). • NDI > 30% (15/50). • Deteriorating radicular neurology. We excluded those with degenerative trophic changes of the cervical spine, focal instability, trauma, osteoporosis, previous cervical spine surgery, previous infection, ossifying axial skeletal disease and inflammatory spondyloarthritides. The device used was an unconstrained implant with stabilizing teeth. Over the 5 years, we studied their postoperative comfort level via the Neck Disability Index (NDI) and Visual Analogue Score (VAS). Pre-operative and post-operative analysis of the sagittal axis and of involved facet joints were done. 22 patients suffered postoperative neck pain as reflected by the NDI and VAS scores. Of these, 10 reported of neck pain even 24 months after surgery. However, none were neurologically worse and all patients returned to their pre-morbid functions and were relieved of pain by 28 months. All 22 patients reported of rapid dissolution of neckache after peri-facetal injections of steroids were done under image guidance. We draw attention to the facet joint as the pain generator, triggered by inappropriate implant height, eccentric stresses via hybrid constructs, eccentric loading due to unconstrained devices and unaddressed Luschka joint degeneration. Such factors require careful selection of patients for surgery, necessitate proper pre-operative templating and call for appropriate technical solutions during surgery

Cervical spine fusion have gained interest in the literature since these procedures are now ever more frequently being performed in an outpatient setting with few complications and acceptable results. The purpose of this study was to assess the rate of blood transfusion after cervical fusion surgery, and its effect, if any on complication rates. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients that underwent cervical fusion surgery from 2010 to 2013. Univariate and multivariate regression analysis was used to determine post-operative complications associated with transfusion and cervical fusion. We identified 11,588 patients who had cervical spine fusion between 2010 and 2013. The overall rate of transfusion was found to be 1.47%. All transfused patients were found to have increased risk of: venous thromboembolism (TBE) (OR 3.19, CI: 1.16–8.77), myocardial infarction (MI) (OR 9.12, CI: 2.53–32.8), increased length of stay (LOS) (OR 28.03, CI: 14.28–55.01) and mortality (OR 4.14, CI: 1.44–11.93). Single level fusion had increased risk of: TBE (OR 3.37, CI: 1.01–11.33), MI (OR 10.5, CI: 1.88–59.89), and LOS (OR 14.79, CI: 8.2–26.67). Multilevel fusion had increased risk of: TBE (OR 5.64, CI: 1.15–27.6), surgical site infection (OR 16.29, CI: 3.34–79.49), MI (OR 10.84, CI: 2.01–58.55), LOS (OR 26.56, CI: 11.8–59.78) and mortality (OR 10.24, CI: 2.45–42.71). ACDF surgery had an increased risk of: TBE (OR 4.87, CI: 1.04–22.82), surgical site infection (OR 9.73, CI: 2.14–44.1), MI (OR 9.88, CI: 1.87–52.2), LOS (OR 28.34, CI: 13.79–58.21) and mortality (OR 6.3, CI: 1.76–22.48). Posterior fusion surgery had increased risk of: MI (OR 10.45, CI: 1.42–77.12) and LOS (OR 4.42, CI: 2.68–7.29). Our results demonstrate that although cervical fusions can be done as outpatient procedures special precautions and investigations should be done for patients who receive transfusion after cervical fusion surgery. These patients are demonstrated to have higher rate of MI, DVT, wound infection and mortality when compared to those who do not receive transfusion

Fresh-frozen allograft bone is frequently used in orthopaedic surgery. We investigated the incidence of allograft-related infection and analysed the outcomes of recipients of bacterial culture-positive allografts from our single-institute bone bank during bone transplantation. The fresh-frozen allografts were harvested in a strict sterile environment during total joint arthroplasty surgery and immediately stored in a freezer at -78º to -68º C after packing. Between January 2007 and December 2012, 2024 patients received 2083 allografts with a minimum of 12 months of follow-up. The overall allograft-associated infection rate was 1.2% (24/2024). Swab cultures of 2083 allografts taken before implantation revealed 21 (1.0%) positive findings. The 21 recipients were given various antibiotics at the individual orthopaedic surgeon’s discretion. At the latest follow-up, none of these 21 recipients displayed clinical signs of infection following treatment. Based on these findings, we conclude that an incidental positive culture finding for allografts does not correlate with subsequent surgical site infection. Additional prolonged post-operative antibiotic therapy may not be necessary for recipients of fresh-frozen bone allograft with positive culture findings.

Cite this article: Bone Joint J 2015;97-B:427–31.

Using the United States Nationwide Inpatient Sample, we identified national trends in revision spinal fusion along with a comprehensive comparison of comorbidities, inpatient complications and surgical factors of revision spinal fusion compared to primary spinal fusion.

In 2009, there were 410 158 primary spinal fusion discharges and 22 128 revision spinal fusion discharges. Between 2002 and 2009, primary fusion increased at a higher rate compared with revision fusion (56.4% vs 51.0%; p < 0.001). In 2009, the mean length of stay and hospital charges were higher for revision fusion discharges than for primary fusion discharges (4.2 days vs 3.8 days, p < 0.001; USD $91 909 vs. $87 161, p < 0.001). In 2009, recombinant human bone morphogenetic protein (BMP) was used more in revision fusion than in primary fusion (39.6% vs 27.6%, p < 0.001), whereas interbody devices were used less in revision fusion (41.8% vs 56.6%, p < 0.001).

In the multivariable logistic regression model for all spinal fusions, depression (odds ratio (OR) 1.53, p < 0.001), psychotic disorders (OR 1.49, p < 0.001), deficiency anaemias (OR 1.35, p < 0.001) and smoking (OR 1.10, p = 0.006) had a greater chance of occurrence in revision spinal fusion discharges than in primary fusion discharges, adjusting for other variables. In terms of complications, after adjusting for all significant comorbidities, this study found that dural tears (OR 1.41; p < 0.001) and surgical site infections (OR 3.40; p < 0.001) had a greater chance of occurrence in revision spinal fusion discharges than in primary fusion discharges (p < 0.001). A p-value < 0.01 was considered significant in all final analyses.

Cite this article: Bone Joint J 2014;96-B:807–16.

The purpose of this study was to investigate the clinical predictors of surgical outcome in patients with cervical spondylotic myelopathy (CSM). We reviewed a consecutive series of 248 patients (71 women and 177 men) with CSM who had undergone surgery at our institution between January 2000 and October 2010. Their mean age was 59.0 years (16 to 86). Medical records, office notes, and operative reports were reviewed for data collection. Special attention was focused on pre-operative duration and severity as well as post-operative persistence of myelopathic symptoms. Disease severity was graded according to the Nurick classification.

Our multivariate logistic regression model indicated that Nurick grade 2 CSM patients have the highest chance of complete symptom resolution (p < 0.001) and improvement to normal gait (p = 0.004) following surgery. Patients who did not improve after surgery had longer duration of myelopathic symptoms than those who did improve post-operatively (17.85 months (1 to 101) vs 11.21 months (1 to 69); p = 0.002). More advanced Nurick grades were not associated with a longer duration of symptoms (p = 0.906).

Our data suggest that patients with Nurick grade 2 CSM are most likely to improve from surgery. The duration of myelopathic symptoms does not have an association with disease severity but is an independent prognostic indicator of surgical outcome.

Cite this article: Bone Joint J 2013;95-B:966–71.

In a retrospective cohort study we compared the clinical outcome and complications, including dysphagia, following anterior cervical fusion for the treatment of cervical spondylosis using either a zero-profile (Zero-P; Synthes) implant or an anterior cervical plate and cage. A total of 83 patients underwent fusion using a Zero-P and 107 patients underwent fusion using a plate and cage. The mean follow-up was 18.6 months (. sd. 4.2) in the Zero-P group and 19.3 months (. sd. 4.1) in the plate and cage group. All patients in both groups had significant symptomatic and neurological improvement. There were no significant differences between the groups in the Neck Disability Index (NDI) and visual analogue scores at final follow-up. The cervical alignment improved in both groups. There was a higher incidence of dysphagia in the plate and cage group on the day after surgery and at two months post-operatively. All patients achieved fusion and no graft migration or nonunion was observed. When compared with the traditional anterior cervical plate and cage, the Zero-P implant is a safe and convenient procedure giving good results in patients with symptomatic cervical spondylosis with a reduced incidence of dysphagia post-operatively. Cite this article: Bone Joint J 2013;95-B:543–7

Objectives. To demonstrate that instrumented fusion of the paediatric cervical spine is possible and can be performed safely. Study Design. A retrospective review of paediatric patients who had instrumented fusion of the cervical spine. Materials and method. Sixteen paediatric patients (10 male, 6 female) with a mean age of 8 years who underwent instrumented cervical fusion were retrospectively reviewed. Surgery was performed for trauma (5 cases), spinal tuberculosis (3 cases), congenital anomalies (6 cases) and malignancies (2 cases). Fixation methods included occipito-cervical fusion, pedicle and lateral mass screws and anterior cervical plating. Ten posterior approaches, four anterior approaches and four combined anterior and posterior approaches were performed. We looked at fusion rates, blood loss, levels fused, theatre time, technique and complications. Results. All patients achieved radiological and clinical fusion. The average number of levels fused was 2.5, blood loss 418ml and theatre time 222 minutes for all patients. Anterior procedures had an average of 1 levels fused, blood loss 117ml and theatre time 98 minutes. Posterior procedures had an average number of 1.9 levels fused, blood loss of 306ml and theatre time of 131 minutes. For the combined anterior and posterior procedures the average levels fused were 5.5, blood loss 975ml and theatre time 248 minutes. Five surgery related complications were encountered. These consisted of dural leaks and wound sepsis which were all treated effectively. Conclusion. The use of modern segmental spinal instrumentation in the paediatric cervical spine is a viable option in this young population. Although our study sample was small we are able to demonstrate that no major surgical complications were encountered due to the use of cervical spinal instrumentation. NO DISCLOSURES

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.

Wrong-level surgery is a unique pitfall in spinal surgery and is part of the wider field of wrong-site surgery. Wrong-site surgery affects both patients and surgeons and has received much media attention. We performed this systematic review to determine the incidence and prevalence of wrong-level procedures in spinal surgery and to identify effective prevention strategies. We retrieved 12 studies reporting the incidence or prevalence of wrong-site surgery and that provided information about prevention strategies. Of these, ten studies were performed on patients undergoing lumbar spine surgery and two on patients undergoing lumbar, thoracic or cervical spine procedures. A higher frequency of wrong-level surgery in lumbar procedures than in cervical procedures was found. Only one study assessed preventative strategies for wrong-site surgery, demonstrating that current site-verification protocols did not prevent about one-third of the cases. The current literature does not provide a definitive estimate of the occurrence of wrong-site spinal surgery, and there is no published evidence to support the effectiveness of site-verification protocols. Further prevention strategies need to be developed to reduce the risk of wrong-site surgery.