Perioperative complications in patients aged ≥85 years undergoing spinal surgery: a retrospective comparative study of pre-old and old patients in Japan.

Study Design: A retrospective comparative study. Purpose: To compare the characteristics of perioperative complications in patients aged ≥85 years with those of younger patients undergoing similar spine surgery and examine factors associated with perioperative complications and clinical outcomes among patients aged ≥85 years. Overview of Literature: The risk factors for perioperative complications and their effect on outcomes in patients aged ≥85 years remain unclear. Furthermore, no study has compared younger patients with similar surgeries and condition with those aged ≥85 years. Methods: The study included patients aged ≥65 years who underwent spinal surgeries. The patients aged ≥85, 75-84, and 65-74 years were categorized into the super-old, old, and pre-old groups, respectively. The differences in perioperative age-related complications were compared among the three groups while matching for surgical procedures and general conditions (study 1). Furthermore, preoperative and intraoperative factors were examined for perioperative complications in the super-old group (study 2). Complications were categorized into surgical site and systemic complications. Results: The analysis included 44 patients from each group. In study 1, the total complication rates were 40.9%, 25%, and 18.2% of the super-old, old, and pre-old groups, respectively. Differences in complication rates were observed between the super-old and pre-old groups (p=0.011). In study 2, 58 patients from the super-old group were analyzed. Surgical site complications were significantly associated with longer surgical duration (p=0.02) and more estimated blood loss (p=0.003). Systemic complications were significantly associated with previous cerebrovascular disease (p=0.014), preoperative motor deficit (p=0.023), and emergency case (p=0.006) and negatively associated with diabetes mellitus (p=0.048). Conclusions: Perioperative complications increased with advancing age in the super-old, old, and pre-old groups. The complication type is associated with specific background factors; therefore, determining them may help prevent perioperative complications.

Which patients do we need to consider augmentation of muscle active potentials regarding transcranial electrical stimulation motor-evoked potentials monitoring before spine surgery?

BACKGROUND CONTEXT: Transcranial electrical stimulation motor-evoked potentials (Tc-MEPs) are the current trend and are important in preventing intraoperative neurological deficits. Posttetanic Tc-MEPs (p-MEP) can augment the amplitudes of compound muscle active potentials (CMAPs), especially in the case of insufficient conventional Tc-MEPs (c-MEP). PURPOSE: To retrospectively investigate pre- and intraoperative factors necessitating p-MEP monitoring and to examine changes in the success rates of baseline Tc-MEP monitoring before and after tetanic stimulation in patients with such factors. STUDY DESIGN: Retrospective observational study. PATIENT SAMPLE: Patients (n=184) who underwent spinal surgery with Tc-MEP monitoring in our department between August 2020 and July 2022. OUTCOME MEASURES: Manual muscle testing (MMT) scores were calculated to identify patients with preoperative motor deficits. c-MEP and p-MEP amplitudes were recorded from the defined muscles. METHODS: We compared preoperative and intraoperative factors between the c-MEP and p-MEP groups (study 1). In cases where the factors were identified, we investigated the success rate of the baseline MEP measurement of each muscle before and after tetanic stimulation (study 2). RESULTS: One hundred fifty-seven patients were included. Of those, 87 showed sufficient CMAPs with c-MEP. Meanwhile, 70 needed p-MEP because of insufficient CMAPs. In univariate analysis, cervical/thoracic surgery (p<.001), preoperative MMT 3 or below (p=.009), shorter duration of illness (p=.037), previous cerebrovascular disease (p=.014), and dialysis (p=.031) were significantly associated with p-MEP group. Preoperative MMT 3 or below was the only factor requiring p-MEP (odds ratio, 3.34; 95% confidence interval, 1.28-8.73, p=.014) in multivariate analysis. In the p-MEP group, 24 patients had preoperative motor deficits; 16 patients with complete data were included in the analysis (study 2). The success rates of MEP monitoring before and after tetanic stimulation of the entire lower-extremity muscles were 42.7 and 57.3%, respectively (p<.001). The success rates for each muscle before and after tetanic stimulation were abductor pollicis brevis: 81.3% and 96.9%, tibialis anterior: 34.4% and 50.0%, gastrocnemius: 25% and 40.6%, and abductor hallucis: 68.8% and 81.3%, respectively. No significant differences were observed in success rates for any of the muscles. CONCLUSIONS: Patients with preoperative MMT 3 or below highly needed p-MEP. The success rate of baseline MEP monitoring increased with tetanic stimulation, even in patients with preoperative motor deficits. We believe that p-MEP monitoring can result in reliable CMAP recording, especially in cases of preoperative motor deficits with MMT scores of 3 or below.

Anterior Placement of Cages in Posterior Lumbar Interbody Fusion for Obtaining Good Lumbar Lordosis Formation.

Introduction: Posterior lumbar interbody fusion (PLIF) is a common treatment for nerve root disease associated with lumbar foraminal stenosis or lumbar spondylolisthesis. At our institution, PLIF is usually performed with high-angle cages and posterior column osteotomy (PLIF with HAP). However, not all patients achieve sufficient segmental lumbar lordosis (SLL). This study determined whether the location of PLIF cages affect local lumbar lordosis formation. Methods: A total of 59 patients who underwent L4/5 PLIF with HAP at our hospital, using the same titanium control cage model, were enrolled in this cohort study. The mean ratio of the distance from the posterior edge of the cage to the posterior wall of the vertebral body/vertebral length (RDCV) immediately after surgery was 16.5%. The patients were divided into two groups according to RDCV <16.5% (group P) and ≥16.5% (group G). The preoperative and 6-month postoperative slip rate (%slip), SLL, local disk angle (LDA), ratio of disk height/vertebral height (RDV), 6-month postoperative RDCV, ratio of cage length/vertebral length (RCVL), and ratio of posterior disk height/anterior disk height at the fixed level (RPA) were evaluated via simple lumbar spine X-ray. The preoperative and 6-month postoperative Japanese Orthopedic Association (JOA) and low back pain visual analog scale (VAS) scores were also evaluated. Results: Groups G and P included 31 and 28 patients, respectively. The preoperative %slip, SLL, LDA, RDV, JOA score, and low back pain VAS score were not significantly different between the groups. In groups G and P, 6-month postoperative %slip, SLL, LDA, RDV, RDCV, RCVL, and RPA were 3.3% and 7.9%, 18.6° and 15.4°, 9.7° and 8.0°, 36.6% and 40.3%, 21.1% and 10.1%, 71.4% and 77.0%, and 56.1% and 67.7%, respectively. The 6-month postoperative SLL, LDA, RDV, RDCV, RCVL, and RPA significantly differed (p=0.03, 0.02, 0.02, <0.001, <0.001, and <0.001, respectively). Conclusions: Anterior PLIF cage placement relative to the vertebral body is necessary for good SLL in PLIF.

The clinical role of preoperative fulcrum-bending and supine side-bending radiographs on the prediction of curve correction in adolescent idiopathic scoliosis.

PURPOSE: Preoperative curve assessment is important in adolescent idiopathic scoliosis (AIS). Our objective is to clarify the role of side-bending radiographs (SBR) and fulcrum-bending radiographs (FBR) in predicting postoperative Cobb angle in nonstructural and structural curves. METHODS: Twenty-five consecutive patients with AIS who underwent correction surgery were included. The Cobb angles of structural and nonstructural curves were determined. Cobb angles were measured based on pre- and postoperative standing anteroposterior radiographs of the whole spine. The Cobb angles of SBR and FBR were measured preoperatively. The difference between the Cobb angle at each bending and the preoperative Cobb angle was defined as the predicted correction angle, whereas the difference between the preoperative Cobb angle and postoperative Cobb angle was defined as the surgical correction angle. The correction index was calculated by dividing the surgical correction angle by the predicted correction angle. The difference between the predicted correction angle and surgical correction angle was defined as the prediction error. We compared SBR and FBR for both structural and nonstructural curves in these terms. RESULTS: For both curves, the predicted correction angle of FBR was significantly higher than that of SBR, and the correction index of FBR was significantly lower than that of SBR. Patients with a correction index close to 1 and small prediction error had undergone FBR in the structural curve and SBR in the nonstructural curve. CONCLUSION: FBR is predictive of postoperative correction angle of the structural curve, whereas SBR is predictive of postoperative correction angle of the nonstructural curve.

Temporal Evolution of White Blood Cell Count and Differential: Reliable and Early Detection Markers for Surgical Site Infection Following Spinal Posterior Decompression Surgery.

Introduction: For early detection of surgical site infection (SSI) following spinal decompression surgery, we compared temporal changes in the values of laboratory markers that are not affected by operative parameters. Methods: The study included 302 patients, which were divided into an SSI group (patients who developed deep SSI) and a non-SSI group for analysis. We reviewed data on C-reactive protein level, total white blood cell (WBC) count, and WBC differential percentage and count before spinal decompression, on postoperative day 1, and on postoperative day 4. We identified laboratory markers that are not affected by operative parameters (operating time, intraoperative blood loss, and number of operative segments). Laboratory markers with a significant difference observed between the peak or nadir value and the value in the subsequent survey day were considered as an indicator of SSI. We examined the utility of each indicator by calculating sensitivity and specificity. Furthermore, we investigated the utility of the combination of all five indicators (wherein the recognition of one marker was considered positive). Results: Temporal changes in five laboratory markers were considered indicators of SSI. The changes from postoperative day 1 to postoperative day 4 were as follows: (1) increased WBC count (42% sensitivity, 88% specificity), (2) increased neutrophil percentage (25% sensitivity, 96% specificity), (3) increased neutrophil count (25% sensitivity, 94% specificity), (4) decreased lymphocyte percentage (25% sensitivity, 95% specificity), and (5) decreased lymphocyte count (25% sensitivity, 85% specificity). The combination of these five markers showed a 50% sensitivity, 81% specificity, and 0.65 AUC. Conclusions: Five markers were found to be reliable indicators of SSI following spinal decompression surgery because they were not affected by operative parameters. The combination of all five indicators had moderate sensitivity and high specificity. Therefore, this may be reliable and useful for the early detection of SSI.

Differential diagnosis between metastatic and osteoporotic vertebral fractures using sagittal T1-weighted magnetic resonance imaging.

BACKGROUND: Magnetic resonance imaging (MRI) is the most helpful for determining the differential diagnosis between metastatic and osteoporotic vertebral fractures; especially whole spine MRI is effective if patients have multiple spinal metastases. However, it is time-consuming to obtain all planes for all metastatic vertebrae. If we can differentiate these metastatic and osteoporotic vertebral fractures based on only one section and signal intensity, it would save time and be effective for patients with pain. This study investigated the usefulness of sagittal T1-weighted MRI findings in differentiating metastatic and osteoporotic vertebral fractures. METHODS: We retrospectively reviewed patients diagnosed with metastatic or osteoporotic vertebral fractures. Findings characteristic of metastatic fractures were considered: (a) pedicle or posterior element involvement; (b) convex posterior border of the vertebral body; (c) epidural infiltration; and (d) diffuse homogeneous low signal intensity; findings characteristic of osteoporotic compression fractures were also considered: (e) low-signal-intensity band and (f) posterior retropulsion. Chi-square test or Fisher's exact probability test was used to investigate the usefulness of each MRI finding. Intra- and inter-observer reliability analysis was performed. RESULTS: This study comprised 43 patients with metastases (45 vertebrae) and 118 patients with osteoporotic fractures (156 vertebrae). All findings showed significant difference with each fracture (p-value: <0.01 to 0.03). Although each MRI finding exhibited high intra- and inter-observer reliability (κ: 0.66 to 1.00), finding (c) exhibited low reliability. Finding (a) showed high sensitivity (88.9%) and usefulness for screening, and findings (b), (d), (e), and (f) showed high specificity (90.4%-100%) and usefulness for definitive diagnosis. CONCLUSIONS: Characteristic findings with sagittal T1-weighted MRI were useful in the differential diagnosis of metastatic and osteoporotic vertebral fractures. To prevent overlooking metastatic fractures with sagittal T1-weighted MRI, findings of the pedicle or posterior element involvement should be focused on because of its reliability and sensitivity.