Pelvic incidence is a risk factor for lower instrumented vertebra failure in adult spinal deformity patients who underwent corrective fusion terminating at the L5 vertebra.

BACKGROUND: Factors related to postoperative mechanical failure after long fusion with lower instrumented vertebra (LIV) at L5 have not been well investigated. Elucidating such factors may allow us to perform alternatives to spinopelvic fusion for adult spinal deformity (ASD) cases. We investigated the incidence and risk factors of LIV failure in patients with ASD who underwent surgical treatment of long corrective fusion until the L5 vertebrae. METHODS: Between 2009 and 2018, 52 patients who underwent corrective fusions to L5 were followed-up for at least one-year. We evaluated the associated patient factors for LIV failure which include loosening of the pedicle screw of LIV, fracture of LIV, distal junctional kyphosis (DJK). RESULTS: The mean age of the participants was 71.2 ± 7.59 (range, 44-84). LIV failure occurred in 20 patients (38.5%), and 6 patients (11.5%) underwent secondary surgery for caudal segments. The mean pelvic incidence (PI) was 52.5 ± 9.8 in the failure group versus 45.3 ± 11.4 in non-failure group (P = 0.02) and pelvic tilt (PT) was 39.1 ± 9.0 versus 32.4 ± 13.0. There were no significant differences in sex, age, body mass index, number of levels fused, and other radiographic data. Logistic regression analysis that included T1 pelvic angle, PT, PI - postoperative LL and PI also identified PI as the only significant determinant of LIV failure (OR = 1.07, P = 0.034). Receiver operating characteristic analysis demonstrated that a PI over 50.0° was associated with LIV failure (sensitivity 63%, specificity 70%, AUC 0.694). CONCLUSION: LIV failure was frequently observed after long corrective fusion for patients with ASD. High PI was found to be a significant risk factor for the LIV failure.

Risk factors for recurrence and regrowth of spinal schwannoma.

BACKGROUND: Spinal schwannoma recurs after initial surgery at a rate of 4%-6%, with known risk factors including subtotal resection, multilevel involvement, large tumor size, and malignant histopathology. This study examined risk factors for schwannoma recurrence and residual tumor regrowth. METHODS: Sixty-five patients who underwent resection of spinal schwannoma in our department between July 2010 and December 2018 and were followed up for more than 1 year were retrospectively analyzed for age, sex, follow-up duration, imaging and surgical data, recurrence, reoperation, and Japanese Orthopaedic Association scores before and 1 year after surgery. Patients with postoperative recurrence or residual tumor regrowth of >10% at the final visit (R+ group) were compared with patients without recurrence or regrowth (R- group). Multivariate logistic regression analysis was performed to analyze concurrent effects of risk factors on recurrence and regrowth. RESULTS: The 65 patients (mean age 52.4 years at surgery) had schwannomas involving cervical (n = 14), thoracic (n = 25), and lumbar (n = 26) spinal levels. Mean follow-up duration was 58 months. Location was intradural in 65%, extradural in 17%, and both intradural and extradural in 18%. There were 4 recurrences (6.2%), and the mean interval between surgery and recurrence was 18.8 months. Seven patients (10.8%) experienced regrowth. Comparing group R+ (n = 11) and group R- (n = 54), univariate analysis showed significant differences in Sridhar tumor classification, giant tumor (Sridhar classification II, IVb, and V), left-right and cranial-caudal tumor size, largest diameter, operative time, blood loss, subtotal resection, reoperation, fusion surgery, and follow-up duration. Multivariate logistic regression analysis revealed giant tumor (Sridhar classification types II, IVb, and V) as an independent risk factor for recurrence and regrowth. CONCLUSIONS: This retrospective review of 65 consecutive patients with spinal schwannoma in a single institution demonstrated that 16.9% had recurrence or regrowth, demonstrating that this potential risk should be kept in mind.

Impact of body mass index on surgical outcomes and complications in adult spinal deformity.

BACKGROUND: Several studies have reported that overweightness and obesity are associated with higher complication rates in lumbar spine surgery. However, little is known about the effect of obesity on postoperative complications in adult spinal deformity (ASD) surgery, especially in the elderly. This study aimed to examine the effect of body mass index (BMI) on surgical outcomes and postoperative complications in elderly ASD patients undergoing surgical correction in Japan. METHODS: We conducted a retrospective, multicenter, observational study of 234 consecutive patients diagnosed with ASD who underwent corrective surgery. Patients were divided into two groups according to BMI, BMI <25 (153 patients, mean age 71.9 years) and BMI ≥ 25 (overweight/obese, 81 patients, mean age 73.3 years). Radiographic results and perioperative complications were compared between the two groups. RESULTS: Surgical complications occurred in approximately 20% of patients in each group; complications did not significantly differ between the two groups. A greater proportion of patients in the BMI ≥ 25 group experienced mechanical failure and DJK, although the difference was not significant. Preoperative mean lumbar lordosis (LL), pelvic incidence (PI) minus LL, sacral slope (SS) and sagittal vertical axis (SVA) were similar in the BMI < 25 and BMI ≥ 25 groups. However, the BMI ≥25 group had lower mean LL (p = 0.015) and higher PI minus LL (p = 0.09) postoperatively. The BMI ≥25 groups also had significantly smaller LL (p = 0.026), smaller SS (p = 0.049) and higher SVA (p = 0.041) at the final follow-up, compared to the BMI < 25 group. CONCLUSIONS: In the present study, no difference in medical or surgical complications after ASD surgery was found between overweight/obese patients (BMI ≥ 25) and those with BMI < 25. However, correction of LL and SVA was smaller in patients with overweight/obese patients.

Sagittal alignment changes and postoperative complications following surgery for adult spinal deformity in patients with Parkinson's disease: a multi-institutional retrospective cohort study.

BACKGROUND: Parkinson's disease (PD) has been found to increase the risk of postoperative complications in patients with adult spinal deformity (ASD). However, few studies have investigated this by directly comparing patients with PD and those without PD. METHODS: In this multicenter retrospective cohort study, we reviewed all surgically treated ASD patients with at least 2 years of follow-up. Among them, 27 had PD (PD+ group). Clinical data were collected on early and late postoperative complications as well as any revision surgery. Radiographic parameters were evaluated before and immediately after surgery and at final follow-up, including sagittal vertical axis (SVA), thoracic kyphosis, lumbar lordosis, sacral slope, and pelvic tilt. We compared the surgical outcomes and radiographic parameters of PD patients with those of non-PD patients. RESULTS: For early complications, the PD+ group demonstrated a higher rate of delirium than the PD- group. In terms of late complications, the rate of non-union was significantly higher in the PD+ group. Rates of rod failure and revision surgery due to mechanical complications also tended to be higher, but not significantly, in the PD+ group (p = 0.17, p = 0.13, respectively). SVA at final follow-up and loss of correction in SVA were significantly higher in the PD+ group. CONCLUSION: Extra attention should be paid to perioperative complications, especially delirium, in PD patients undergoing surgery for ASD. Furthermore, loss of correction and rate of non-union were greater in these patients.

Prognostic factors for neurological outcome after anterior decompression and fusion for proximal-type cervical spondylotic amyotrophy - A retrospective analysis of 77 cases.

BACKGROUND: Decompression through an anterior approach is theoretically effective for the surgical treatment of cervical spondylotic amyotrophy (CSA), because the pathology usually locates at the anterior side. However, most previous studies investigated posterior surgery or a mix of anterior surgery and posterior surgery in their investigation. Only a few small case series have investigated the surgical outcomes of anterior decompression and fusion (ADF). Therefore, we conducted a multicenter retrospective study that included patients who underwent ADF for proximal-type CSA. METHODS: We analyzed the outcomes of 77 consecutive spinal surgeries performed on proximal-type CSA patients who underwent ADF. Preoperative and postoperative manual muscle tests (MMT) and the patients' backgrounds, radiological findings, and complications were reviewed. We divided the cases into two groups, good-outcome group (MMT improvement â‰§ 2 or improved to MMT 5) and poor-outcome group (others) and evaluated the prognostic factors for outcomes. RESULTS: Of the 77 patients, 48 (62%) showed good neurological outcome. Multiple compressive lesions at anterior horn (AH) and/or ventral nerve roots (VNRs) were detected in 66 patients (85.7%) on the magnetic resonance images. The patients with a single compressive lesion at VNR or AH tended to show good neurological recovery when compare to those with multiple lesions. Age and duration of symptoms were related to the poor outcome in univariate analysis. Duration of symptoms was an independent factor associated with postoperative neurological outcome. The cut-off value for poor outcome was 7.0 months for the symptom duration (sensitivity: 79%, specificity: 54%, area under the curve: 0.69). CONCLUSIONS: Patients with proximal-CSA were more likely to have multiple compressive lesions at an AH and/or a VNR. The prognostic factor for poor neurological outcome was duration of symptoms of ≥7 months.

Effect of bisphosphonates or teriparatide on mechanical complications after posterior instrumented fusion for osteoporotic vertebral fracture: a multi-center retrospective study.

BACKGROUND: The optimal treatment of osteoporosis after reconstruction surgery for osteoporotic vertebral fractures (OVF) remains unclear. In this multicentre retrospective study, we investigated the effects of typically used agents for osteoporosis, namely, bisphosphonates (BP) and teriparatide (TP), on surgical results in patients with osteoporotic vertebral fractures. METHODS: Retrospectively registered data were collected from 27 universities and affiliated hospitals in Japan. We compared the effects of BP vs TP on postoperative mechanical complication rates, implant-related reoperation rates, and clinical outcomes in patients who underwent posterior instrumented fusion for OVF. Data were analysed according to whether the osteoporosis was primary or glucocorticoid-induced. RESULTS: A total of 159 patients who underwent posterior instrumented fusion for OVF were included. The overall mechanical complication rate was significantly lower in the TP group than in the BP group (BP vs TP: 73.1% vs 58.2%, p = 0.045). The screw backout rate was significantly lower and the rates of new vertebral fractures and pseudoarthrosis tended to be lower in the TP group than in the BP group. However, there were no significant differences in lumbar functional scores and visual analogue scale pain scores or in implant-related reoperation rates between the two groups. The incidence of pseudoarthrosis was significantly higher in patients with glucocorticoid-induced osteoporosis (GIOP) than in those with primary osteoporosis; however, the pseudoarthrosis rate was reduced by using TP. The use of TP also tended to reduce the overall mechanical complication rate in both primary osteoporosis and GIOP. CONCLUSIONS: The overall mechanical complication rate was lower in patients who received TP than in those who received a BP postoperatively, regardless of type of osteoporosis. The incidence of pseudoarthrosis was significantly higher in patients with GIOP, but the use of TP reduced the rate of pseudoarthrosis in GIOP patients. The use of TP was effective to reduce postoperative complications for OVF patients treated with posterior fusion.

Analysis of swallowing function after anterior/posterior surgery for cervical degenerative disorders and factors related to the occurrence of postoperative dysphagia.

BACKGROUND CONTEXT: Dysphagia is one of the postoperative complications of cervical degenerative disorders. However, few studies have evaluated the pre- and postoperative swallowing function in detail. PURPOSE: To analyze pre- and postoperative swallowing dynamics kinetically and investigate factors associated with postoperative dysphagia in patients with cervical degenerative disorders. STUDY DESIGN: Retrospective review of prospectively collected data. PATIENT SAMPLE: A total of 41 consecutive patients who underwent an anterior approach (anterior cervical discectomy/corpectomy and fusion (ACDF, ACCF), hybrid surgery (ACDF+ACCF) and total disc replacement) and 44 consecutive patients who underwent a posterior approach (laminoplasty and laminoplasty/laminectomy with fusion). OUTCOME MEASURES: We compared the pre- and postoperative functional oral intake scale (FOIS), dysphagia severity scale (DSS), esophageal dysphagia, anterior/superior hyoid movement, upper esophageal sphincter (UES) opening, pharyngeal transit time, bolus residue scale (BRS), and the number of swallows. METHODS: Videofluoroscopy was performed on the day before surgery and within two weeks after surgery. Data related to age, gender, disease, surgical procedure, surgical site, operative time, and blood loss were collected from the medical records. Pre- and postoperative data were compared for each item in the anterior and posterior approaches. The odds ratio of dysphagia after an anterior approach was also calculated. RESULTS: In the anterior approach, DSS, FOIS, the anterior and superior hyoid movements, maximum UES opening, BRS, and number of swallows worsened postoperatively (p<.05, respectively). In the posterior approach, DSS, FOIS, the anterior hyoid movement, and BRS worsened postoperatively (p<.05, respectively). The factors associated with dysphagia were a proximal surgical site above C3 (OR: 14.40, CI: 2.84-73.02), blood loss >100 mL (OR: 9.60, CI: 2.06-44.74), an operative time >200 minutes (OR: 8.18, CI: 1.51-44.49), and an extensive surgical field of more than three intervertebral levels (OR: 6.72, CI: 1.50-30.07). The decline in swallowing function after the posterior approach was related to aging (p=.045). CONCLUSIONS: Each approach may decrease swallowing function, especially because of the limitation on the anterior hyoid movement. Dysphagia after anterior approaches was associated with the operative site, operative time, and blood loss.

The lower Osteotomy Level is Associated With Decreased Revision Surgery Due to Mechanical Complications After Three-Column Osteotomy in Patients With Adult Spinal Deformity: A Multi-Institutional Retrospective Study.

STUDY DESIGN: A multi-institutional retrospective study. OBJECTIVES: To investigate risk factors of mechanical failure in three-column osteotomy (3COs) in patients with adult spinal deformity (ASD), focusing on the osteotomy level. METHODS: We retrospectively reviewed 111 patients with ASD who underwent 3COs with at least 2 years of follow-up. Radiographic parameters, clinical data on early and late postoperative complications were collected. Surgical outcomes were compared between the low-level osteotomy group and the high-level osteotomy group: osteotomy level of L3 or lower group (LO group, n = 60) and osteotomy of L2 or higher group (HO group, n = 51). RESULTS: Of the 111 patients, 25 needed revision surgery for mechanical complication (mechanical failure). A lower t-score (odds ratio [OR] .39 P = .002) and being in the HO group (OR 4.54, P = .03) were independently associated with mechanical failure. In the analysis divided by the osteotomy level (LO and HO), no difference in early complications or neurological complications was found between the two groups. The rates of overall mechanical complications, rod failure, and mechanical failure were significantly higher in the HO group than in the LO group. After propensity score matching, mechanical complications and failures were still significantly more observed in the HO group than in the LO group (P = .01 and .029, respectively). CONCLUSIONS: A lower t-score and osteotomy of L2 or higher were associated with increased risks of mechanical failure. Lower osteotomy was associated with better correction of sagittal balance and a lower rate of mechanical complications.

Growth factor-free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia.

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.

Growth factor free, peptide-functionalized gelatin hydrogel promotes arteriogenesis and attenuates tissue damage in a murine model of critical limb ischemia.

Critical limb ischemia (CLI) occurs when blood flow is restricted through the arteries, resulting in ulcers, necrosis, and chronic wounds in the downstream extremities. The development of collateral arterioles (i.e. arteriogenesis), either by remodeling of pre-existing vascular networks or de novo growth of new vessels, can prevent or reverse ischemic damage, but it remains challenging to stimulate collateral arteriole development in a therapeutic context. Here, we show that a gelatin-based hydrogel, devoid of growth factors or encapsulated cells, promotes arteriogenesis and attenuates tissue damage in a murine CLI model. The gelatin hydrogel is functionalized with a peptide derived from the extracellular epitope of Type 1 cadherins. Mechanistically, these "GelCad" hydrogels promote arteriogenesis by recruiting smooth muscle cells to vessel structures in both ex vivo and in vivo assays. In a murine femoral artery ligation model of CLI, delivery of in situ crosslinking GelCad hydrogels was sufficient to restore limb perfusion and maintain tissue health for 14 days, whereas mice treated with gelatin hydrogels had extensive necrosis and autoamputated within 7 days. A small cohort of mice receiving the GelCad hydrogels were aged out to 5 months and exhibited no decline in tissue quality, indicating durability of the collateral arteriole networks. Overall, given the simplicity and off-the-shelf format of the GelCad hydrogel platform, we suggest it could have utility for CLI treatment and potentially other indications that would benefit from arteriole development.

Upper limb gangrene due to a subclavian arterial thrombosis associated with thoracic outlet syndrome following cervical spondylotic amyotrophy.

Thoracic outlet syndrome (TOS) refers to an abnormal compression of the subclavian vessels and the brachial plexus at the base of the neck or thoracic outlet. The authors described a novel case of a 66-year-old male with arterial TOS and unilateral upper rib dysplasia following cervical spine disease. Owing to the comorbidity of cervical spondylotic amyotrophy and a history of sloping shoulder due to rib dysplasia, TOS occurred, which subsequently led to subclavian arterial thrombosis and eventually resulted in the gangrene of the hand. Thrombectomy and surgical resection of the first and second ribs avoided the progression of further neurovascular disorder. When treating a cervical spondylotic patient, concurrent TOS can be obscured by symptoms caused by cervical lesions, leading to difficulty in identifying the origin of these neurovascular findings. The possibility of subsequent thromboembolic events based on TOS should be considered, especially in cases with dysplasia of the upper ribs.

Comparison of Lateral Lumbar Interbody Fusion and Posterior Lumbar Interbody Fusion as Corrective Surgery for Patients with Adult Spinal Deformity-A Propensity Score Matching Analysis.

Lateral lumbar interbody fusion (LLIF) is increasingly performed as corrective surgery for patients with adult spinal deformity (ASD). This paper compares the surgical results of LLIF and conventional posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) in ASD using a propensity score matching analysis. We retrospectively reviewed patients with ASD who received LLIF and PLIF/TLIF, and investigated patients' backgrounds, radiographic parameters, and complications. The propensity scores were calculated from patients' characteristics, including radiographic parameters and preoperative comorbidities, and one-to-one matching was performed. Propensity score matching produced 21 matched pairs of patients who underwent LLIF and PLIF/TLIF. All radiographic parameters significantly improved in both groups at the final follow-up compared with those of the preoperative period. The comparison between both groups demonstrated no significant difference in terms of postoperative pelvic tilt, lumbar lordosis (LL), or pelvic incidence-LL at the final follow-up. However, the sagittal vertical axis tended to be smaller in the LLIF at the final follow-up. Overall, perioperative and late complications were comparable in both procedures. However, LLIF procedures demonstrated significantly less intraoperative blood loss and a smaller incidence of postoperative epidural hematoma compared with PLIF/TLIF procedures in patients with ASD.

Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study.

Various studies have found a high incidence of early graft dislodgement after multilevel corpectomy. Although a hybrid fusion technique was developed to resolve implant failure, the hybrid and conventional techniques have not been clearly compared in terms of perioperative complications in patients with severe ossification of the posterior longitudinal ligament (OPLL) involving three or more levels. The purpose of this study was to compare clinical and radiologic outcomes between anterior cervical corpectomy with fusion (ACCF) and anterior hybrid fusion for the treatment of multilevel cervical OPLL. We therefore retrospectively reviewed the clinical and radiologic data of 53 consecutive patients who underwent anterior fusion to treat cervical OPLL: 30 underwent ACCF and 23 underwent anterior hybrid fusion. All patients completed 2 years of follow-ups. Implant migration was defined as subsidence > 3 mm. There were no significant differences in demographics or clinical characteristics between the ACCF and hybrid groups. Early implant failure occurred significantly more frequently in the ACCF group (5 cases, 16.7%) compared with the hybrid group (0 cases, 0%). The fusion rate was 80% in the ACCF group and 100% in the hybrid group. Although both procedures can achieve satisfactory neurologic outcomes for multilevel OPLL patients, hybrid fusion likely provides better biomechanical stability than the conventional ACCF technique.

Locking of the Distal Radioulnar Joint Caused by Dorsal Tear of the Triangular Fibrocartilage Complex: A Case Report.

CASE: We encountered a case of locking of the distal radioulnar joint after a traumatic injury that restricted the supination and pronation of the wrist. The locking was released surgically with a good 2-year outcome. We found a tear between the dorsal aspect of the joint capsule and the triangular fibrocartilage complex (TFCC). The tear allowed the TFCC to displace volarly and become entrapped against the volar aspect of the ulnar head. CONCLUSION: The open approach facilitated visualization and understanding of this unusual injury pattern and allowed direct repair. Joint incongruity may not occur despite a locked joint.

Surgical stabilization of spinal metastasis in diffuse idiopathic skeletal hyperostosis ("Mets-on-DISH"): Two case reports.

RATIONALE: Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by ossification along the anterolateral aspect of at least 4 contiguous vertebral bodies. A fracture involving the fused vertebra in patients with DISH often leads to severe instability and spinal cord injury. Spinal metastasis (Mets) and DISH can coexist in elderly patients and increase their risk of pathologic vertebral fractures. However, there are few reports on concomitant spinal Mets and DISH. PATIENT CONCERNS: A 78-year-old man who complained of gradual onset of paraparesis, sensory loss below the umbilicus, and incontinence (case 1) and a 63-year-old woman who complained of severe back pain and urinary incontinence (case 2). DIAGNOSIS: Two patients were diagnosed with spinal Mets and DISH. INTERVENTIONS: Decompression surgery was performed at the metastatic sites in case 1 whereas instrumentation surgery was performed in case 2 despite the fracture having a benign appearance with no associated neurologic symptoms. OUTCOMES: A vertebral fracture developed at the metastatic vertebra after decompression surgery in case 1. Severe instability of the surgical site in this case resulted in persistent paralysis even after subsequent revision surgery with instrumentation. In contrast, the clinical course was benign without any neurologic dysfunction at the 2-year follow-up in case 2. LESSONS: Instrumentation surgery should be performed in patients with DISH who develop spinal Mets even if there is no apparent instability.

Identification of Predictive Factors for Mechanical Complications After Adult Spinal Deformity Surgery: A Multi-Institutional Retrospective Study.

STUDY DESIGN: A retrospective multicenter observational study. OBJECTIVE: To investigate correction surgeries that were performed in relatively aged patients in terms of mechanical complications (MCs) and their predictive factors. SUMMARY OF BACKGROUND DATA: The risk factors associated with MCs have not yet been well examined, especially in aged populations. METHODS: We retrospectively reviewed 230 surgically treated ASD patients with an average age of 72.2 years. Twenty-eight patients with ASD caused by vertebral fractures were excluded. The minimum follow-up was 2 years. Postoperative MCs were defined as proximal junction kyphosis, distal junction kyphosis, pseudoarthrosis, rod breakage, and vertebral fractures. We divided all the ASD patients into two groups: patients with MC (the MC (+) group) and patients without MC (the MC (-) group). Radiographic parameters were evaluated before and immediately after surgery. The SRS-Schwab ASD classification and global alignment and proportion (GAP) score were also evaluated. RESULTS: Of the 202 patients, 91 (45.0%) had MCs. The age at surgery was significantly higher in the MC (+) group than in the MC (-) group. Regarding radiographic parameters, postoperative global tilt (GT), pre- and postoperative thoracolumbar kyphosis (TLK), and postoperative thoracic kyphosis were significantly higher in the MC (+) group than in the MC (-) group. Other parameters, such as the proposed ideal alignment target of PI-LL<10, did not significantly affect MC rates. The GAP score was high in both groups and not significantly related to a higher rate of MC. Forward stepwise logistic regression indicated that the age at surgery, postoperative GT, and preoperative TLK were significant risk factors for MCs. CONCLUSION: Older age, higher postoperative GT, and higher pre and postoperative TLK can be risk factors for MCs. The GAP score was high in both groups and not significantly related to a higher rate of MC. LEVEL OF EVIDENCE: 4.

Is Modified K-line a Powerful Tool of Surgical Decision Making for Patients With Cervical Spondylotic Myelopathy?

STUDY DESIGN: Prospective observational single-center study. OBJECTIVE: To evaluate anterior decompression and fusion (ADF) or posterior surgery (PS) for patients with cervical spondylotic myelopathy (CSM) using the modified K-line (mK-line) and to compare clinical and radiologic outcomes between these 2 techniques. SUMMARY OF BACKGROUND DATA: The authors have previously reported that insufficient posterior decompression is often seen after laminoplasty for CSM in patients with preoperative anterior clearance of the spinal cord <4 mm on the basis of the mK-line. However, to our knowledge, no study has investigated the role, if any, of the mK-line in surgical decision making for patients with CSM. METHODS: A total of 87 patients were enrolled who underwent surgery for treatment of CSM between 2011 and 2015 at our hospital and who could be followed up for at least 2 years. ADF was selected as a more favorable procedure than PS in patients with anterior spinal clearance of <4 mm on preoperative midsagittal magnetic resonance imaging. On the basis of the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy, the rate of recovery of the JOA scores at 2 years after surgery was investigated as a clinical outcome to compare these 2 groups. RESULTS: Mean age was 65.1 (±12.9) years in the ADF group (n=26) and 70.5 (±8.6) years in the PS group (n=61). In the PS group, 10 patients underwent posterior decompression with fusion. Mean preoperative and postoperative JOA scores were 10.5 and 14.1 points in the ADF group and 9.8 and 13.1 points in the PS group, respectively, showing no significant difference in recovery rate of JOA score between the ADF (58.9%) and PS (47.1%) groups. However, patients with a minimum interval between the mK-line and the anterior compression factor on the midsagittal image (minimum interval of the spinal cord) <4 mm tended to have unsatisfactory outcomes (recovery rate 29.6%) compared with patients with minimum interval of the spinal cord >4 mm (53.6%, P=0.07) in the PS group. CONCLUSION: Preoperative intervention using the mK-line is useful to predict residual cord compression and might homogenize postoperative clinical outcomes in both anterior surgery and PS.

Spinal Cord Infarction with Aortic Dissection.

Spinal cord infarction is an uncommon but devastating disorder caused by various conditions. Aortic dissection is a possible etiological factor and is usually associated with severe chest or back pain. We encountered two cases of spinal cord infarction associated with aortic dissection that presented without typical severe pain, and each case resulted in a different clinical course. Aortic dissection should be considered a cause of spinal cord infarction even if there is little or no pain. The different outcomes in our two patients reflected a difference in their initial functional scores.

Methicillin-Resistant Staphylococcus aureus Nasal Swab and Suction Drain Tip Cultures in 4573 Spinal Surgeries: Efficacy in Management of Surgical Site Infections.

STUDY DESIGN: A retrospective single-center study. OBJECTIVE: To assess the diagnostic value of methicillin-resistant Staphylococcus aureus (MRSA) nasal swab and suction drain tip cultures. SUMMARY OF BACKGROUND DATA: The prognostic value of MRSA nasal swab and suction drain tip cultures has not been firmly established in spinal surgery. METHODS: This study retrospectively included 4573 consecutive patients who underwent spinal surgery between January 2008 and December 2014. Patients diagnosed with infectious disease were excluded. Prophylactic antibiotics were administered intraoperatively and postoperatively for 48 hours. MRSA nasal swab cultures were taken from all patients before surgery. Drains were removed when the volume of postoperative fluid drainage was less than 50 mL in the preceding 24 hours and cultures were made. Surgical site infection (SSI) was defined according to Centers for Disease Control and Prevention criteria. RESULTS: SSI was identified in 94 cases (2.1%) and bacteria were isolated in 87 cases (92.6%). Positive MRSA nasal swab cultures were identified in 49 cases (1.1%). There was no significant difference in the SSI positivity rate between the MRSA nasal swab culture (+) and (-) groups. Positive drain tip cultures were found in 382 cases (8.4%), 28 of which developed SSI. There was a significant difference in the SSI positivity rate between the drain tip culture (+) and (-) groups. The sensitivity of drain tip culture was 29.8% and the specificity was 92.1%. In 16 of the 28 patients in the SSI (+) group with positive drain cultures, the same bacteria were isolated from the surgical site, giving a bacteria matching rate of 57.1%. CONCLUSION: MRSA nasal swab and drain tip cultures were not useful for predicting SSI. However, drain tip culture had a high positivity rate in the SSI group and the coincidence rate for the causative pathogen was relatively high. LEVEL OF EVIDENCE: 4.