Dynamics of surgical smoke in the operating room during spinal surgery: Comparison of particulate matter 2.5-air concentration between the electric scalpel with and without a smoke evacuation pencil: A cross-sectional study.

BACKGROUND: Surgical smoke is a vaporous by-product generated during tissue incision and cauterization with an electric scalpel. This smoke contains tissue- and blood/vascular-derived substances, bacteria, viruses, and chemical substances. Among them, it contains many fine particles called particulate matter (PM) 2.5, which are harmful and hazardous to the human body. We aimed to investigate the occurrence of PM2.5 in surgical smoke produced during spinal surgery and to evaluate the efficacy of an electric scalpel with a smoke evacuation pencil. METHODS: In this retrospective observational study, 89 patients who underwent spinal surgery between June 2019 and May 2021 were included. A dust monitor was installed in the operating room to measure the PM2.5 air concentration during the surgery. During each surgery, the total amount of PM2.5, the maximum PM2.5 air concentration, the exposure time to PM2.5, and the average value of PM2.5 air concentration from the start to the end of the surgery were calculated. RESULTS: We found that in 29 of the 89 cases (32.6%), the air concentration of PM2.5 increased to a level that could cause health damage during the surgery. Twelve cases (13.4%) reached the level that could cause serious health damage, and 8 cases (9%) reached an emergency warning level. The total amount and the maximum and average levels of PM2.5 were significantly suppressed in the surgery with a smoke evacuation pencil group than in the surgery without a smoke evacuation pencil group. CONCLUSION: We detected hazardous levels of PM2.5 in the air during spinal surgery, highlighting the importance of considering smoke control or reduction during spinal surgery. We recommend using an electric scalpel with a smoke evacuation pencil for regulating PM2.5 levels in the operating room.

Large aortic pseudoaneurysm after fusion surgery for hyperextension-type lumbar fracture in diffuse idiopathic skeletal hyperostosis: illustrative case.

BACKGROUND: This study aimed to report an aortic pseudoaneurysm, a rare but lethal complication, after a spinal fracture in ankylosing spine. OBSERVATIONS: An 83-year-old obese woman presented with dementia and was nonambulatory after a fall. She was transported to the hospital, and imaging showed a hyperextension-type L1 fracture with diffuse idiopathic skeletal hyperostosis (DISH). After posterior fusion surgery using percutaneous pedicle screws, screw loosening was detected 10 days postoperatively. Fracture dislocation was reduced by changing to transdiscal screws and rodding while in the lateral position. However, the anterior opening persisted. Enhanced computed tomography performed at 6 weeks postoperatively showed a large aortic pseudoaneurysm extending into the vertebral fracture site without screw loosening. Neither endovascular aortic repair nor open surgery was applicable. The patient was transferred to a sanatorium and died of pneumonia 5 months postoperatively without aortic aneurysm rupture. LESSONS: An aortic pseudoaneurysm can occur in hyperextension-type spinal fractures in DISH, even after fusion surgery, when the edge of the fracture is in contact with the aortic wall. The anterior opening dislocation should be reduced as much as possible.

Neoadjuvant teriparatide therapy targeting the osteoporotic spine: influence of administration period from the perspective of bone histomorphometry.

OBJECTIVE: Teriparatide (TPTD) is a potent promoter of early-stage osteogenesis and may be a useful adjuvant therapy to reduce complications related to bone fragility in spinal surgery patients with osteoporosis. However, effective neoadjuvant TPTD therapy regimens remain poorly understood. This study aimed to examine the effect of preoperative TPTD administration on cancellous bone with bone histomorphometry and to clarify the timing of preoperative TPTD administration for patients with spinal fusion and osteoporosis. METHODS: In this longitudinal multicenter study, 57 patients with spinal fusion and osteoporosis, who consented to undergo iliac biopsy, were allocated to the following treatment groups: neoadjuvant TPTD therapy group (n = 42) and no neoadjuvant therapy (NTC) group (n = 15). Patients in the TPTD group were categorized into subgroups on the basis of duration of preoperative TPTD administration, as follows: 1 month (n = 9), 2 months (n = 8), 3 months (n = 9), 4 months (n = 7), and 6 months (n = 9). All patient samples were preoperatively double labeled with tetracycline, and iliac biopsies were performed during spinal fusion surgery. Histomorphometric analyses were performed on nondecalcified, thin-sliced specimens. Specimens were classified on the basis of TPTD administration duration and subsequently compared with those of the NTC group. Postoperative complications and Oswestry Disability Index scores were evaluated at 1 and 2 years after surgery. RESULTS: There were no demographic differences between groups. Mineralizing surface/bone surface, a key parameter of dynamic bone formation, started to increase after 1 month of TPTD administration; this increase became significant after 3 months of administration and peaked at 4 months, with a 6-fold increase relative to that of the NTC group. The patients who received preoperative TPTD for 3 months or more had superior clinical results in terms of the osteoporotic complication rate and Oswestry Disability Index scores, except for bisphosphonate-pretreated patients. CONCLUSIONS: When considering neoadjuvant TPTD therapy, the authors recommend at least 3 months of preoperative administration to provide a more substantial anabolic effect from the early postoperative stage.

Rib Hyperostosis as a Risk Factor for Poor Prognosis in Cervical Spine Injury Patients With Diffuse Idiopathic Skeletal Hyperostosis.

STUDY DESIGN: Retrospective multi-center study. OBJECTIVE: To identify the morphological features of costovertebral joints and ribs in surgically managed cervical injury patients with diffuse idiopathic skeletal hyperostosis (DISH) and to examine its impact on their vital prognosis. SUMMARY OF BACKGROUND DATA: Several reports have indicated that DISH is an independent risk factor for mortality after spinal fracture. The reason for the high mortality in cervical injury patients with DISH is unclear, although some reports have suggested a possible association between pulmonary complications and mortality. METHODS: From 1999 to 2017, a total of 50 DISH patients (44 males) with cervical spine injuries who underwent spinal surgery were enrolled (average age 74 yrs). Prognosis and clinical risk factor data were collected; the morphological features of the patients' costovertebral joints and ribs were evaluated with computed tomography. The influence of each proposed risk factor and thoracic morphological feature on mortality was tested with univariate and multivariate analyses. RESULTS: The survival rate at 5 years after surgery was 52.3%. Nineteen (38%) patients died, and the most common cause of death was pneumonia (68%). Costovertebral bone excrescences and rib hyperostosis were found to be thoracic pathognomonic signs; their frequencies were 94% and 82%, respectively, and these conditions occurred in an average of 7.0 joints and 4.7 bones, respectively. The results of the log-rank test showed a significant difference in age, injury severity score (ISS), costovertebral bone excrescences, and rib hyperostosis. The results of age-adjusted multivariate analysis indicated that age (hazard ratio [HR] = 8.65, 95% confidence interval [CI] = 1.10-68.28, P = 0.041) and rib hyperostosis (HR = 3.82, 95% CI = 1.38-10.57, P = 0.010) were associated with mortality. CONCLUSION: Reduced chest wall mobility associated with rib hyperostosis in cervical spine injury patients with DISH leads to a poor prognosis. LEVEL OF EVIDENCE: 3.

Clinicopathological features of lipomas with gene fusions involving HMGA2.

BACKGROUND: Despite accumulating knowledge of chimeric genes derived from fusion of the HMGA2 gene with multiple partners in lipomas, the different clinicopathological features of lipomas depending on different gene aberrations have not been well documented. The purpose of this study was to examine the clinical significance of the expression of fusion genes in lipomas. PATIENTS AND METHODS: The expressions of three previously reported gene fusion transcripts, including HMGA2/LPP, HMGA2/RDC1 and HMGA2/NFIB, were analyzed in 102 tumors from patients with lipomas. RESULTS: There were 23 cases (22.5%) expressing HMGA2/LPP, 2 cases (1.9%) expressing HMGA2/RDC1 and no cases of HMGA2/NFIB expression (0%). There were no significant intergroup differences in age, gender, body mass index, tumor size or location. The magnetic resonance images and pathological features were also not different in regard to the status of fusion gene expression. CONCLUSION: There were no significant differences of clinicopathological features in patients with lipoma with or without these fusion gene transcripts.

Focal lymphoid hyperplasia in a lipoma, mimicking liposarcoma.

Lipomas may contain nonadipose tissue, which can confound the correct imaging diagnosis because features of such neoplasms can mimic findings associated with well-differentiated liposarcomas. Intratumoral nonadipose tissue, such as muscle, cartilage, and fibrous tissue, may be present in lipomas; however, lymphoid hyperplasia in a lipoma is extremely rare. This report describes a case involving a heterogeneous lipoma in a 55-year-old woman in whom the heterogeneous portion of the tumor was in fact a reactive lymphoid hyperplasia encased by the lipoma. The imaging features of this lesion as well as pathological findings of this unusual tumor are discussed.

Contact pressure in anterior cruciate ligament bone tunnels: comparison of endoscopic and two-incision technique.

PURPOSE: To investigate differences in contact pressure in the bone tunnel between the inside-out and outside-in techniques used for anterior cruciate ligament reconstruction. TYPE OF STUDY: In vitro cadaveric analysis. METHODS: Four fresh-frozen cadaver knees were tested. A femoral tunnel was generated through the tibial tunnel (inside-out technique). Another femoral tunnel was created using a rear-entry guide at the same intra-articular exit (outside-in technique). Aluminum cylinders containing 4-way (anterior, posterior, medial, and lateral) conductive rubber pressure sensors at the entrance of the joint were inserted into the tibial and femoral tunnels. Dynamic changes in the contact pressure of grafts in the femoral and tibial tunnels during 0 degrees to 130 degrees of knee flexion were measured. RESULTS: Contact pressure of the graft migrated from the anterior to the posterior portion of the femoral tunnel upon alignment of the femoral and tibial tunnels. At 0 degrees, 30 degrees, and 60 degrees of knee flexion, significantly greater contact pressure was observed at the anterior portion of the femoral tunnel made by the inside-out technique compared with that in the tunnel made by the outside-in technique. At 0 degrees, 30 degrees, and 60 degrees of knee flexion, significantly greater contact pressure was observed at the lateral portion of the femoral tunnel made by the outside-in technique. Constant contact pressure was observed in the medial portion of the tunnel made by the inside-out technique. Pressure changes in the tibial tunnel were slight; moreover, changes were not influenced by the femoral tunnel direction under any conditions. CONCLUSIONS: This study shows that contact pressure in the femoral tunnel is influenced by the direction of the femoral tunnel. CLINICAL RELEVANCE: The femoral tunnel direction in anterior cruciate ligament reconstruction is an important factor for femoral tunnel enlargement. A horizontal direction of the femoral tunnel might be needed for mature bone graft incorporation.

Extraskeletal osteosarcoma of the jaw.

Extraskeletal osteosarcoma is a rare malignancy, which accounts for 1-2% of all soft tissue sarcomas; occurrence of these tumors in the head and neck is extremely rare. We present a case of extraskeletal osteosarcoma arising in the subcutaneous tissue of the jaw angle, the central portion of which displayed calcification. Imaging findings were interesting in terms of a high grade malignancy in that the tumor was small and well circumscribed; its appearance mimicked a calcified lymph node. The differential diagnosis of this lesion as well as the imaging and pathological features of extraskeletal osteosarcoma are discussed.

Pathological fracture of the femur ten years after successful radiation therapy for metastatic breast cancer.

We describe a case involving a 75-year-old woman presenting with a femur fracture 10 years after radiation therapy for metastatic breast cancer, which developed in the right femur. The lesion showed complete response with bone healing following radiation therapy; however, the patient sustained a femur fracture ten years later. Histological examination of the specimens obtained from the lesion revealed features of radiation osteonecrosis, but there was no histological evidence of tumor. To our knowledge, there has been no reported case of pathological fracture ten years after radiation therapy from radiation osteonecrosis rather than progression of the metastatic lesion. Late complications of radiation therapy should be considered with care, even when metastatic lesions demonstrate complete response to treatment.

Properties of the tibial component regarding impact load.

Load transmission through knee prostheses was examined to clarify how the tibial component behaves under dynamic loading conditions. We did Genesis II total knee arthroplasty using sawbones and measured impact load transmission ratios using the split-Hopkinson pressure bar technique. We also measured the polyethylene strain when an impact load was applied using a strain gauge bonded to the anterior surface of the polyethylene. The impact load transmission ratios of metal-backed and all-polyethylene tibial components were less than 4%. Greater load transmission was observed with metal-backed components, which suggests that some of the applied dynamic load is transferred directly to the tibial cortical bone. Increasing polyethylene thickness decreased impact load transmission ratios in both components, which might lower the cancellous bone stresses beneath tibial implants. Greater strain in the tibial component was observed in all-polyethylene components. Increased polyethylene thickness did not significantly decrease the polyethylene strain, probably because of the nonlinear elastic behavior of the polyethylene material. The distant positioning of the strain gauge may, however, have prevented the detection of local contact strains. Recent clinical studies did not confirm our theoretical predictions, suggesting that other factors contribute more significantly to the clinical outcome in current total knee arthroplasty.

MR imaging findings of an unusual case of myositis ossificans presenting as a progressive mass with features of fluid-fluid level.

We present a case of myositis ossificans involving the upper arm in which features of fluid-fluid level became apparent on magnetic resonance imaging (MRI). Serial MR images obtained over a 6-month period exhibited progressive appearances in the absence of dense mineralization in the early and mid phases, which simulate neoplastic conditions. Twenty-four weeks following the biopsy, MR images revealed that the mass had decreased in size with the disappearance of most of the features of fluid-fluid level. To the best of our knowledge, no example of myositis ossificans accompanied by features of fluid-fluid level, which was closely monitored by MRI, exists in the literature. These features of image examination should be evaluated cautiously to avoid unnecessary surgical intervention, especially in instances where lesions exhibit expansive appearance. This case provided beneficial information regarding the sequence of changes in terms of MR appearance of myositis ossificans.

Influence of the femoral tunnel location and angle on the contact pressure in the femoral tunnel in anterior cruciate ligament reconstruction.

BACKGROUND: The causes of bone tunnel enlargement after anterior cruciate ligament reconstruction have not been thoroughly investigated. HYPOTHESIS: A malpositioned femoral tunnel and an acute femoral tunnel angle may increase the mechanical stress in the femoral tunnel. STUDY DESIGN: Controlled laboratory study. METHODS: Three femoral tunnels (normal, anterior, and acute) and the tibial tunnel were made in four fresh-frozen cadaveric knees. Aluminum cylinders containing pressure-sensitive conductive rubber sensors at the joint entrance were inserted into the femoral tunnels. Dynamic changes in the contact pressure of the graft in the femoral tunnel were measured. RESULTS: Peak contact pressures and dynamic changes in contact pressure for the normal and anterior femoral tunnels demonstrated no differences. Maximum contact pressure of the graft was observed at the anterior portion with the knee in full extension and at the posterior portion with deep knee flexion. Consistent contact pressure occurred at the anterior aspect of the acute femoral tunnel throughout the range of motion. Mean contact pressure at the anterior region of the acute femoral tunnel was significantly higher than that of the normal femoral tunnel at 60 degrees, 90 degrees, and 120 degrees of knee flexion. CONCLUSIONS: The consistent contact pressure in the anterior aspect of the acute femoral tunnel may erode the anterior portion of the femoral tunnel, resulting in bone tunnel enlargement. CLINICAL RELEVANCE: The femoral tunnel direction in anterior cruciate ligament reconstruction is an important factor in reducing femoral tunnel enlargement.

Intraoperative measurements of knee motion in total knee arthroplasty.

A photostereometric technology-based knee motion analysis system was developed and intraoperative kinematics during total knee arthroplasty (TKA) was investigated. Ten knees were evaluated and two different types of posterior-cruciate-retaining TKA (Genesis-I and Genesis-II) were used. Both TKA showed posterior translation of the medial and lateral femoral condyle with knee flexion. The motion pattern of the estimated contact point of Genesis-II was small initial rollback followed by sliding motion, then rollback again more than 60 degrees. In Genesis-II, the amount of translation of the medial condyle was significantly larger than that of the lateral, suggesting that the lateral condyle acted as a rotational pivot. Our developed knee motion analysis system was non-contact, high resolution and can evaluate both kinematics and estimated contact pattern. The results of this study suggest that intraoperative measurement using this analysis system has advantages for the investigation of in-vivo kinematics and contact condition in TKA.

Rotational muscle strength of the limb after anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon.

PURPOSE: To investigate the influence of harvesting semitendinosus and gracilis tendons on the rotational muscle strength of the limb after anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Prospective study. METHODS: We performed a prospective study of 62 consecutive (34 male, 28 female) patients with ACL reconstructions using the semitendinosus and gracilis tendons. The mean age at surgery was 20.8 years. The semitendinosus tendon was harvested in 32 patients (ST group), and semitendinosus and gracilis tendons in 30 patients (STG group). The peak isokinetic torques for extension, flexion, internal rotation, and external rotation were measured before and 12 months after ACL reconstruction using the Cybex 6000B system (Cybex Division of Lumex, Ronkonkoma, NY). The rotational torque was measured at 30 degrees/sec and 120 degrees/sec. RESULTS: Before reconstruction, the mean isokinetic peak torque of the involved limb was decreased in extension and internal rotation. The mean isokinetic peak torque of the involved limb in extension recovered 12 months after ACL reconstruction; however, the weakness in internal rotation persisted. The preoperative weakness of the involved limb in extension and internal rotation recovered in the male patients, but not in the female patients after postoperative rehabilitation. The peak torque of the involved limb in internal rotation was decreased in the STG group, but not in the ST group. CONCLUSIONS: The internal rotational torque was influenced by harvesting the semitendinosus and gracilis tendons after ACL reconstruction, especially in female patients and patients from whom the gracilis tendon was harvested. Semitendinosus and gracilis tendons are important for the internal rotation of the limb and it was difficult to compensate for this function. Thus, we recommend harvesting the semitendinosus tendon only if tendon quality is sufficient to further minimize harvesting morbidity.