Metabolic and Endocrine Disorders in Pseudarthrosis

The Ideal Threshold of Hemoglobin A1C in Diabetic Patients Undergoing Elective Lumbar Decompression Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate the association of Hemoglobin A1C (HbA1c) with surgical site infection (SSI) and patient-reported outcomes (PROs), and to identify optimal HbA1c thresholds to minimize the risk of SSI and maximize PROs.

SUMMARY OF BACKGROUND DATA

Diabetes mellitus has been associated with worsened outcomes following spine surgery. HbA1c, a surrogate of glycemic control, is an important assessment tool in diabetic patients.

METHODS

A single-center, retrospective cohort study using prospectively collected data was undertaken. Diabetic patients undergoing elective lumbar decompression surgery between October 2010 and May 2021 were included. HbA1c, demographics, comorbidities, and perioperative data were collected. Primary outcomes included: 1) SSI, and 2) PROs, including the Numeric Rating Scale (NRS)-back/leg pain and Oswestry Disability Index (ODI). Secondary outcomes included: complications, readmissions, and reoperations within 90-days postoperatively. The minimum clinically important difference (MCID) was set at a 30% improvement from baseline PROs.

RESULTS

Of 1819 patients who underwent lumbar decompression surgery, 368 patients had diabetes mellitus, and 177 had a documented preoperative HbA1c value. Of patients with available HbA1c values, the mean age was 62.5±12.3, the mean HbA1c value was 7.2±1.5%, and SSI occurred in 3 (1.7%) patients only, which prevented further analysis of SSI and HbA1c. A significant association was seen with a higher HbA1c and failure to achieve NRS-Back pain MCID30 [Odds ratio(OR)=0.53, 95% confidence interval(CI) 0.42-0.78; P =0.001] and ODI MCID30 (OR=0.58, 95%CI 0.44-0.77; P =0.001), but not NRS-Leg pain MCID30 (OR=1.29, 95%CI 0.86-1.93; P =0.208). ROC-curve analysis and Youden's index revealed an HbA1c threshold of 7.8 for NRS-Back pain MCID30 (AUC=0.65, P <0.001) and 7.5 for ODI MCID30 (AUC=0.65, P =0.001).

CONCLUSIONS

In diabetic patients undergoing elective lumbar decompression surgery, HbA1c levels above 7.8 and 7.5 were associated with less improvement of NRS-Back and ODI scores at 12-months postoperatively, respectively. To optimize PROs, We recommend a preoperative HbA1c of 7.5 or below for diabetic patients undergoing elective lumbar decompression surgery.

In Vivo Evidence of Early Instability and Late Stabilization in Motion Segments Immediately Superior to Anterior Cervical Arthrodesis

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

The aim was to identify patient factors that affect adjacent segment kinematics after anterior cervical discectomy and fusion (ACDF) as measured by biplane radiography.

SUMMARY OF BACKGROUND DATA

The etiology of adjacent segment disease (ASD) may be multifactorial. Previous studies have investigated associations between patient factors and ASD, although few attempted to link patient factors with mechanical changes in the spine that may explain ASD development. Previous studies manually measured intervertebral motion from static flexion/extension radiographs, however, manual measurements are unreliable, and those studies failed to measure intervertebral motion during rotation.

METHODS

Patients had continuous cervical spine flexion/extension and axial rotation movements captured at 30 images per second in a dynamic biplane radiography system preoperatively and 1 year after ACDF. Digitally reconstructed radiographs generated from subject-specific computed tomography scans were matched to the biplane radiographs using a validated tracking process. Dynamic kinematics and preoperative disc height were calculated from this tracking process. Preoperative magnetic resonance imagings were evaluated for disc bulge. Patient age, sex, body mass index, smoking status, diabetes, psychiatric history, presence of an inciting event, and length of symptoms were collected. Multivariate linear regression was performed to identify patient factors associated with 1-year postoperative changes in adjacent segment kinematics.

RESULTS

Sixty-three patients completed preoperative and postoperative testing. Superior adjacent segment disc height and disc bulge predicted the change in superior adjacent segment range of motion after surgery. Inferior adjacent segment disc bulge, smoking history, and the use of psychiatric medications predicted the change in inferior adjacent segment flexion/extension range of motion after surgery.

CONCLUSIONS

Preexisting adjacent segment disc degeneration, as indicated by disc height and disc bulge, was associated with reduced adjacent segment motion after ACDF, while lack of preexisting adjacent disc degeneration was associated with increased adjacent segment motion after ACDF. These findings provide in vivo evidence supporting early instability and late stabilization in the pathophysiology of disc degeneration.

Incisional negative pressure wound therapy to reduce surgical-site infections in major limb amputations: a meta-analysis

Purpose

Incisional negative pressure wound therapy (iNPWT) has shown effectiveness in the treatment of high-risk surgical wounds. Especially patients with diabetes-induced peripheral arterial disease undergoing major limb amputation have a high intrinsic risk for post-surgical wound infections. While normal gauze wound dressings do not cause stimulation of microvasculature, iNPWT might improve wound healing and reduce wound complications. The purpose of this study was to systematically review the literature for rates of wound complications and readmissions, as well as post-surgical 30-day mortality.

Methods

We conducted a systematic review searching the Cochrane, PubMed, and Ovid databases. Inclusion criteria were the modified Coleman methodology Score >60, non-traumatic major limb amputation, and adult patients. Traumatic amputations and animal studies were excluded. Relevant articles were reviewed independently by referring to the title and abstract. In a meta-analysis, we compared 3 studies and 457 patients.

Results

A significantly overall lower rate of postoperative complications is associated with usage of iNPWT (odds ratio (OR) = 0.52; 95% CI: 0.30-0.89; P = 0.02). There was no significant improvement for 30-day mortality, when iNPWT was used (OR= 081; 95% CI: 0.46 - 1.45; P = 0.48). Nevertheless, we did not note a significant difference in the readmission rate or revision surgery between the two groups.

Conclusion

Overall, the usage of iNPWT may reduce the risk of postoperative wound complications in major lower limb amputations but does not improve 30-day mortality rates significantly. However, to anticipate surgical-site infection, iNPWT has shown effectiveness and thus should be used whenever applicable.

Optimal hemoglobin A1C target in diabetics undergoing elective cervical spine surgery

BACKGROUND CONTEXT

Diabetes mellitus (DM) is a well-established risk factor for suboptimal outcomes following cervical spine surgery. Hemoglobin A1C (HbA1c), a surrogate for long-term glycemic control, is a valuable assessment tool in diabetic patients.

PURPOSE

In patients undergoing elective cervical spine surgery, we sought to identify optimal HbA1c levels to: (1) maximize 1-year postoperative patient-reported outcomes (PROs), and (2) predict the occurrence of medical and surgical complications.

STUDY DESIGN/SETTING

A retrospective cohort study using prospectively collected data was performed in a single academic center.

PATIENT SAMPLE

Diabetic patients undergoing elective anterior cervical fusion and posterior cervical laminectomy and fusion (PCLF) between October 2010-March 2021 were included.

OUTCOME MEASURES

Primary outcomes included Numeric Rating Scale (NRS)-Neck pain, NRS-Arm pain, and Neck Disability Index (NDI). Secondary outcomes included surgical site infection (SSI), complications, readmissions, and reoperations within 90-days postoperatively.

METHODS

HbA1c, demographic, comorbidity, and perioperative variables were gathered in diabetic patients only. PROs were analyzed as continuous variables and minimum clinically difference (MCID) was set at 30% improvement from baseline.

RESULTS

Of 1992 registry patients undergoing cervical surgery, 408 diabetic patients underwent cervical fusion surgery. Anterior: A total of 259 diabetic patients underwent anterior cervical fusion, 141 of which had an available HbA1c level within one year prior to surgery. Mean age was 55.8±10.1, and mean HbA1c value was 7.2±1.4. HbA1c levels above 6.1 were associated with failure to achieve MCID for NDI (AUC=0.77, 95%CI 0.70-0.84, p<.001), and HbA1c levels above 6.8 may be associated with increased odds of reoperation (AUC=0.61, 95%CI 0.52-0.69, p=.078). Posterior: A total of 149 diabetic patients underwent PCLF, 65 of which had an available HbA1c level within 1 year. Mean age was 63.6±9.2, and mean HbA1c value was 7.2±1.5. Despite a low AUC for NRS-Arm pain and readmission, HbA1c levels above 6.8 may be associated with failure to achieve MCID for NRS-Arm pain (AUC=0.61, 95%CI 0.49-0.73, p=.094), and HbA1c levels above 7.6 may be associated with higher readmission rate (AUC=0.63, 95%CI 0.50-0.75, p=.185).

CONCLUSIONS

In a cohort of diabetic patients undergoing elective cervical spine surgery, HbA1c levels above 6.1 were associated with decreased odds of achieving MCID for NDI in anterior cervical fusion surgery. Though only moderate associations were seen for the select outcomes of reoperation (6.8), readmission (7.6), and MCID for NRS-Arm pain (6.8), preoperative optimization of HbA1c using these levels as benchmarks should be considered to reduce the risk of complications and maximize PROs for patients undergoing elective cervical spine surgery.

Does Preoperative Bone Mineral Density Impact Fusion Success in Anterior Cervical Spine Surgery? A Prospective Cohort Study

OBJECTIVE

The purpose of this study was to identify risk factors for pseudarthrosis in patients undergoing anterior cervical discectomy and fusion (ACDF) with a focus on the role of bone mineral density (BMD) on arthrodesis.

METHODS

We retrospectively reviewed a prospectively collected database of patients undergoing 1- to 4-level ACDF for degenerative indications between 2012 and 2018 at a single institution. All patients were required to have undergone a preoperative dual-energy x-ray absorptiometry (DEXA) scan. Fusion status was assessed on computed tomography (CT) scans obtained 1 year postoperatively. Patients were divided into subgroups based on fusion status and compared on the basis of demographic, BMD, and surgical variables to determine risk factors for pseudarthrosis.

RESULTS

We identified 79 patients for inclusion in this study. Fusion was achieved in 65 patients (82%), while 14 patients (18%) developed pseudarthrosis. The pseudarthrosis subgroup demonstrated significantly lower BMD than their counterparts who achieved successful fusion in both mean hip (-1.4 ± 1.2 vs. -0.2 ± 1.2, respectively; P = 0.002) and spine T-scores (-0.8 ± 1.8 vs. 0.6 ± 1.9, respectively; P = 0.02). The pseudarthrosis group had a substantially higher proportion of patients with osteopenia (57.1% vs. 20.0%) and osteoporosis (21.5% vs. 6.2%; P < 0.001) than the fusion group. Multivariate analysis demonstrated osteopenia (odds ratio [OR] 8.76, P = 0.04), osteoporosis (OR 9.97, P = 0.03), and low BMD (OR 11.01, P = 0.002) to be associated with an increased likelihood of developing pseudarthrosis.

CONCLUSIONS

The results of this study suggest that both osteopenia and osteoporosis are associated with increased rates of pseudarthrosis in patients undergoing elective ACDF.

Pseudarthrosis of the Cervical Spine

Pseudarthrosis of the cervical spine represents a common and challenging problem for spine surgeons. Rates vary greatly from as low as 0%-20% to >60% and depend heavily on patient factors, approach, and number of levels. While some patients remain asymptomatic from pseudarthrosis, many require revision surgery due to instability, continued neck pain, or radiculopathy/myelopathy. We aimed to provide a practical, narrative review of cervical pseudarthrosis to address the following areas: (1) definitions, (2) incidence, (3) risk factors, (4) presentation and workup, (5) treatment decision-making, and (6) postoperative care. It is our hope the current review provides a concise summary for how to diagnose and treat challenging cervical nonunions.

Osteosynthesis or non-operative treatment of the fibula for distal lower-leg fractures with tibial nailing: a systematic review and meta-analysis

Fibular fixation to treat distal lower-leg fractures is a controversial intervention. To ensure better stability itself, better rotational stability, and to prevent secondary valgus dislocation – all these are justifications for addressing the fibula via osteosynthesis. High surgical costs followed by increased risks are compelling reasons against it. The purpose of this study was to systematically review the literature for rates of malunion and malrotation, as well as infections and nonunions.

We conducted a systematic review searching the Cochrane, PubMed, and Ovid databases. Inclusion criteria were modified Coleman Methodology Score (mCMS) > 60, a distal lower-leg fracture treated by nailing, and adult patients. Biomechanical and cadaver studies were excluded. Relevant articles were reviewed independently by referring to title and abstract. In a meta-analysis, we compared five studies and 741 patients.

A significantly lower rate of valgus/varus deviation is associated with fixation of the fibula (OR = 0.49; 95% CI: 0.29–0.82; p = .006). A higher risk for pseudarthrosis was revealed when the fibula underwent surgical therapy, but not significantly (OR = 1.46; 95% CI: 0.76–2.79; p = .26). Nevertheless, we noted an increased risk of postoperative wound infection following fibular plating (OR = 1.90; 95% CI: 1.21–2.99; p = .005). There was no statistically significant difference in the rate of nonunions between the two groups.

Overall, the stabilization of the fibula may reduce secondary valgus/varus dislocation in distal lower-leg fractures but is associated with an increased risk of postoperative wound infections. The indication for fibula plating should be made individually.

Cite this article: EFORT Open Rev 2021;6:816-822. DOI: 10.1302/2058-5241.6.210003

Prognosis of Symptomatic Pseudarthrosis Observed at 1 Year After Lateral Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to investigate the prognosis of symptomatic pseudarthrosis observed at 1 year after lateral lumbar interbody fusion (LLIF) surgery and to analyze the risk factors for persistent pseudarthrosis for 2 years postoperatively.

SUMMARY OF BACKGROUND DATA

Few articles have evaluated the prognosis of symptomatic pseudarthrosis following LLIF surgery.

METHODS

One hundred fifty-two patients with a minimum follow-up of 2 years were screened. Fusion status was assessed at 1 year postoperatively, and unfused segments were reevaluated at 2 years postoperatively. Dynamic x-rays and computed tomography images were acquired to evaluate the fusion status. Demographic data were evaluated to identify the risk factors associated with persistent pseudarthrosis. Clinical outcomes, including the visual analog scale (VAS) for back/leg pain and the Oswestry disability index (ODI), were evaluated preoperatively and at 1 and 2 years postoperatively.

RESULTS

Symptomatic pseudarthrosis was detected in 42 patients at 1 year postoperatively. Among them, 23 patients (54.8%) exhibited solid bony fusion 2 years postoperatively without further intervention. Fourteen patients (33.3%) showed asymptomatic pseudarthrosis, and the remaining five patients (11.9%) showed symptomatic pseudarthrosis. Multivariable analysis showed that diabetes (adjusted odds ratio [OR]: 2.817, P = 0.007), smoking (adjusted OR: 6.497, P = 0.008), and fusion at more than three levels (adjusted OR: 2.525, P = 0.031) were risk factors for persistent pseudarthrosis. Improvements in the VAS scores for back pain and ODI scores were significantly lower in the persistent pseudarthrosis group than in the final solid fusion group at 2 years postoperatively.

CONCLUSION

It is not necessary to intervene for all patients in whom symptomatic pseudarthrosis is detected at 1 year postoperatively because only 11.9% of them will show persistent symptomatic pseudarthrosis. However, early revision surgery should be considered when severe symptomatic pseudarthrosis associated with diabetes, smoking, and fusion at more than three levels is present.Level of Evidence: 4.

Miniplate-Augmented Interlaminar Fusion in C1-C2 Screwing

OBJECTIVE

The interlaminar fusion combination involving C1-C2 screwing fixation is one of the most effective techniques for atlantoaxial dislocation or subluxation, and the bone graft is usually stabilized by wiring constructs. However, some adverse events were reported during the insertion of sublaminar wiring, such as accidentally damaging the spinal cord or dura. Thus we used the miniplate to stabilize the harvest bone graft on the C1-C2 laminar, which led to a shorter operation time and prevented spinal canal violation. This study investigated the safety and efficacy of the novel surgical technique, namely miniplate-augmented interlaminar fusion.

METHODS

We retrospectively reviewed 43 patients who underwent posterior atlantoaxial fusion with the miniplate-augmented iliac crest autograft at our institute. Complications related to surgery were recorded and calculated. After operation, patients were followed up through routine radiography to examine whether the fusion of the atlantoaxial segment was achieved. Success of fusion was defined as follows: 1) the presence of bone bridging between the bone graft and both the atlas and axis; and 2) the absence of movement of the atlantoaxial spinous process on flexion-extension radiography, which meant that the variation of length measured in 2 views, respectively, was <1 mm. The first time when radiography showed successful fusion after surgery was termed as fusion time and was recorded individually. In addition, overall fusion rates and mean fusion times were analyzed.

RESULTS

Of 43 patients, long-term follow-up data were available for 31 patients, whereas the remaining 12 patients had dropped out (mean follow-up duration, 24.91 months; range, 6-72 months). Among 31 patients, 22 (70.96%) were women and 9 (29.03%) were men. The mean age was 63.33 years. Regarding the etiology, atlantoaxial dislocations or subluxations were caused due to degeneration, rheumatoid arthritis, odontoid fracture, trauma, and os odontoideum in 14 (45%), 3 (10%), 5 (16%), 8 (26%), and 1 (3%) patient(s), respectively. Successful fusion was achieved in 30 (96.77%) patients, with a mean fusion time of 6.23 months, whereas only 1 (3.23%) patient did not meet the fusion criteria. No complications related to the miniplate occurred. We noted vertebral artery rupture not requiring blood transfusion in 1 patient, aspiration pneumonia in 1 patient, urinary tract infection in 1 patient, anemia requiring transfusion in 1 patient, and leg dysesthesia in 1 patient. No neurologic deficit was found.

CONCLUSIONS

Miniplate-augmented interlaminar fusion with C1-C2 screwing resulted in excellent fusion rates with a considerably low probability of complications. Hence this novel technique for bone graft fixation with atlantoaxial screwing has a good efficacy and safety and can serve as an alternative for bone graft fixation during C1-C2 fusion.

The use of demineralised bone fibres (DBF) in conjunction with supercritical carbon dioxide (SCCO2) treated allograft in anterior lumbar interbody fusion (ALIF)

Spinal fusion is a common procedure for the treatment of various spinal pathologies. Since the early days, spinal fusion has been carried out with the use of bone grafts as interbody spacers. With the development of synthetic interbody implants, bone grafts were used to facilitate fusion. Although autograft provides the best outcomes for fusion, allografts have been sought after due to donor site morbidity and other shortcomings. Currently, a vast variety of demineralised bone matrix (DBM) products are available with their methods of processing and preparation impacting their properties and clinical outcomes. Demineralised bone fibres (DBF), a form a DBM can be easily packed into implants when mixed with other substances such as allograft bone and patient's blood providing a scaffold for the mixture. We report two cases of anterior lumbar interbody fusion (ALIF) utilising a titanium-polyetheretherketone (PEEK) interbody cage filled with DBF, allograft and patient's blood with a maximum of 12 months follow-up outcome.