Recurrence rate after posterior percutaneous screw fixation without anterior debridement for pyogenic spondylitis compared with conservative treatment: a propensity score-matched analysis.

PURPOSE: Previous studies have shown that percutaneous pedicle screw (PPS) posterior fixation without anterior debridement for pyogenic spondylitis can improve patient quality of life compared with conservative treatment. However, data on the risk of recurrence after PPS posterior fixation compared with conservative treatment is lacking. The aim of this study was to compare the recurrence rate of pyogenic spondylitis after PPS posterior fixation without anterior debridement and conservative treatment. METHODS: The study was conducted under a retrospective cohort design in patients hospitalized for pyogenic spondylitis between January 2016 and December 2020 at 10 affiliated institutions. We used propensity score matching to adjust for confounding factors, including patient demographics, radiographic findings, and isolated microorganisms. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence of pyogenic spondylitis during the follow-up period in the matched cohort. RESULTS: 148 patients (41 in the PPS group and 107 in the conservative group) were included. After propensity score matching, 37 patients were retained in each group. PPS posterior fixation without anterior debridement was not associated with an increased risk of recurrence compared with conservative treatment with orthosis (HR, 0.80; 95% CI, 0.18-3.59; P = 0.77). CONCLUSIONS: In this multi-center retrospective cohort study of adults hospitalized for pyogenic spondylitis, we found no association in the incidence of recurrence between PPS posterior fixation without anterior debridement and conservative treatment.

Acute non-traumatic spinal subarachnoid hematomas: A report of five cases and a systematic review of literature.

BACKGROUND: There is a lack of evidence on spinal subarachnoid hematomas because of the rarity of their spontaneous development and difficulty in diagnosis. The aim of this study was to identify the characteristics and outcomes of surgically confirmed acute non-traumatic spinal subarachnoid hematomas from a multicenter surgical database and conduct a systematic review of existing literature. METHODS: Five surgically confirmed cases of acute non-traumatic spinal subarachnoid hematomas were identified from our multicenter database with 22 cases from a systematic review of existing literature. RESULTS: The mean age of the 27 patients was 59 years. The length of the hematoma was longer than five vertebrae in 70% of the patients, most commonly distributed in the thoracic spine; 63% of all cases were idiopathic, 30% were under anticoagulant therapy, and the remaining 7% presented with coagulation abnormalities. As many as 70% of the patients showed some improvement in neurological symptoms after surgery during a mean follow-up period of 14 months. CONCLUSIONS: This study elucidated the characteristics of acute non-traumatic spinal subarachnoid hematomas in patients who were surgically confirmed. Most patients were middle-aged, complained of back pain, and had the hematoma located in the thoracic spine. Seventy percent of the patients in this study had some improvement in their neurological status, most likely due to surgical decompression and hematoma evacuation.

Neurological severity evaluation using magnetic resonance imaging in acute spontaneous spinal epidural haematomas.

PURPOSE: This study aimed to elucidate the severity of neurological deficits in a large series of patients with acute spontaneous spinal epidural haematoma (SSEH) using magnetic resonance imaging (MRI). METHODS: We included 57 patients treated for acute SSEH at 11 institutions and retrospectively analysed their demographic and MRI data upon admission. We investigated MRI findings, such as the haematoma length and canal occupation ratio (COR). The neurological severity of SSEH was assessed based on the American Spinal Injury Association score on admission. RESULTS: Of the 57 patients, 35 (61%) presented with severe paralysis. The MRI analysis showed that SSEH was often located in the cervical spine, dorsal to the spinal cord, and spread over more than three vertebrae. No differences in age, sex, and aetiology were found between patients with and without severe paralysis. The hypo-intensity layer encircling the haematoma, intra-haematoma heterogeneity, and increased CORs were observed more frequently in the severe paralysis group. Furthermore, pathological examination of a dissected haematoma from one patient with a hypo-intensity layer revealed a collagen layer around the haematoma, and patients with intra-haematoma heterogeneity were more likely to have a bleeding predisposition. CONCLUSIONS: In this large series of patients with SSEH, we identified some MRI features associated with severe paralysis, such as the hypo-intensity layer, intra-haematoma heterogeneity, and increased COR. Accordingly, patients with these MRI characteristics should be considered for early surgical intervention.

Bone-femoral component interface gap after sagittal mechanical axis alignment is filled with new bone after cementless total knee arthroplasty.

PURPOSE: This study retrospectively evaluated the fate of mismatch between an uncemented femoral component and each femoral cut surface (i.e., wedge-shaped gap) relative to sagittal mechanical alignment in total knee arthroplasty (TKA). METHODS: Primary TKA was performed on 99 consecutive knees. The femoral components were aligned to the sagittal mechanical axis with CT-based navigation. All patients were assessed with postoperative true lateral radiographs. Bone-side surfaces of the uncemented femoral component were divided into five zones: anterior flange, anterior chamfer, posterior chamfer, posterior part, and distal part, which were defined as zones 1 to 5, respectively. Bone filling of wedge-shaped gaps in each zone was evaluated after 1 year. RESULTS: Femoral anterior notching did not occur. However, wedge-shaped gaps were observed in at least one zone in 23 of 99 knees (23%), most frequently in zone 5 (18%). There were 9 and 7 gaps in zones 1 and 2, respectively. The femoral component showed malpositioning of approximately 3° of flexion in cases with wedge-shaped gaps in zones 2 and/or 5. After one year, 67% (6/9) of zone 1, 100% (7/7) of zone 2, and 94% (17/18) of zone 5 wedge-shaped gaps were filled in with new bone. CONCLUSIONS: Femoral alignment relative to sagittal mechanical axis caused wedge-shaped gaps due to unstable anterior bone cutting through hard bone, but the small gaps were not clinically significant and filled in within one year. Sagittal setting of the femoral component should aim for the anatomical axis rather than the mechanical axis. LEVEL OF EVIDENCE: IV.

Is a "sulcus cut" technique effective for determining the level of distal femoral resection in total knee arthroplasty?

PURPOSE: Determining the level of distal femoral resection is crucial when performing total knee arthroplasty (TKA). However, variations in distal femoral resection are encountered unexpectedly. A "sulcus cut" technique is sometimes used to determine the level of distal femoral resection, but its effectiveness has not been evaluated. The aim of this study was to examine the reliability of the sulcus cut technique using computer simulation for preoperative planning. METHODS: This study group comprised 40 knees in 34 patients (22 women, 12 men) scheduled for TKA. The preoperative planning software of a computed tomography (CT)-based navigation system was used. We determined the resected level of the femur so that the bone-implant interface of the femoral component was adjusted to the deepest subchondral bone of the trochlear groove in coronal CT images. We then measured each perpendicular distance from the resected surface of the proximal femur to the most distal point of the lateral and medial femoral condyles. RESULTS: The mean distances of the distal-lateral and distal-medial condylar resections from the femoral sulcus were 7 mm (±1 mm) and 8 mm (±1 mm), respectively. The resection level did not differ significantly between men and women or between different component sizes. There was a slightly positive correlation between the femoral mechanical and anatomical axis angle and the distance of the distal-lateral condylar resection from the femoral sulcus. CONCLUSIONS: The sulcus cut technique can be used to determine the desirable level of the distal femoral resection in TKA. LEVEL OF EVIDENCE: Case series, Level IV.

Tibial rotational alignment was significantly improved by use of a CT-navigated control device in total knee arthroplasty.

This study compared the accuracy of three methods to set tibial component rotational alignment: (1) conventional method, the anteroposterior (AP) axis was determined by the surgeon using anatomical landmarks; (2) partial-navigation method, the tibia was prepared according to the AP axis using a CT-based navigation system and the component was manually positioned; (3) full-navigation method, the tibial component was positioned and fixed with cement under the control of navigation using a newly developed instrument. The conventional method showed considerable deviation (range, -18.6° to 14.7°), and the partial-navigation method also showed considerable deviation (-11.3° to 8.1°). In contrast, the full-navigation method significantly improved the accuracy of alignment (-2.9° to 2.1°). The tibial component can become malaligned during cement fixation, even after proper bone preparation.

Prognostic Factors after Surgical Treatment for Spinal Metastases.

STUDY DESIGN: A retrospective multicenter case series was conducted. PURPOSE: This study aimed to investigate survival and prognostic factors after surgery for a metastatic spinal tumor. OVERVIEW OF LITERATURE: Prognostic factors after spinal metastasis surgery remain controversial. METHODS: A retrospective multicenter study was conducted. The study participants included 345 patients who underwent surgery for spinal metastases from 2010 to 2020 at nine referral spine centers in Japan. Data for each patient were extracted from medical records. To identify the factors predicting survival prognosis after surgery, univariate analyses were performed using a Cox proportional hazards model. RESULTS: The mean age was 65.9 years. Common primary tumors were lung (n=72), prostate (n=61), and breast (n=39), and 67.8% (n=234) presented with osteolytic lesions. The epidural spinal cord compression scale score 2 or 3 was recognized in 79.0% (n=271). Frankel grade A paralysis accounted for 1.4% (n=5), and 73.3% (n=253) were categorized as intermediate or high risk according to the new Katagiri score. The overall survival rates were -71.0% at 6 months, 57.4% at 12, and 43.3% at 24. In the univariate analysis, Frankel grade A (hazard ratio [HR], 3.59; 95% confidence interval [CI], 1.23-10.50; p<0.05), intermediate risk (HR, 3.34; 95% CI, 2.10-5.32; p<0.01), and high risk (HR, 7.77; 95% CI, 4.72-12.8; p<0.01) in the new Katagiri score were significantly associated with poor survival. On the contrary, postoperative chemotherapy (HR, 0.23; 95% CI, 0.15-0.36; p<0.01), radiation therapy (HR, 0.43; 95% CI, 0.26-0.70; p<0.01), and both adjuvant therapy (HR, 0.21; 95% CI, 0.14-0.32; p<0.01) were suggested to improve survival. CONCLUSIONS: Surgical indications for patients with Frankel grade A or intermediate or high risk in the new Katagiri score should be carefully considered because of poor survival. Chemotherapy or radiation therapy should be considered after surgery for better survival.

Risk factors for preoperative neurological impairment in patients with spinal meningioma: A retrospective multicenter study.

BACKGROUND: Patients with spinal meningioma may present preoperatively with paralysis and sensory deficits. However, there is a paucity of detailed evaluations and a lack of consensus regarding imaging findings that are predictive of neurological symptoms in patients with spinal meningioma. METHODS: Herein, a total of 55 patients who underwent surgical resection of spinal meningiomas in eight hospitals between 2011 and 2021 were enrolled. Patient characteristics, degree of muscle weakness, sensory disturbances, and the presence of bowel/bladder dysfunction (BBD) before surgical treatment were evaluated using medical records. Patients with American Spinal Injury Impairment Scale grades A-C and the presence of BBD were classified into the paralysis (+) group. Patients with sensory disturbances were assigned to the sensory disturbance (+) group. Based on magnetic resonance (MR) and computed tomography images, the tumor location was classified according to the spinal level and its attachment to the dura mater. To evaluate tumor size, the tumor occupation ratio (OR) was calculated using the area and distance measurement method in horizontal MR images, and the maximum length and area of the tumor in the sagittal plane were measured. RESULTS: Of all patients, 85 % were women. The mean age of patients at surgery was 69.7 years. Twenty-eight (51 %) and 41 (75 %) patients were classified into the paralysis (+) and sensory disturbance (+) groups, respectively. The average tumor length and area in the sagittal plane were 19.6 mm and 203 mm2, respectively; OR-area and diameters were 70.3 % and 72.3 %, respectively. In univariate analyses, tumor length and area in the sagittal plane were significant risk factors for paralysis. OR-diameter, symptom duration, and a low MIB-1 index correlated with sensory disturbances. Multivariate logistic regression analysis demonstrated that the area and length of the tumor in the sagittal plane were significantly correlated with paralysis, whereas the OR-diameter and symptom duration significantly correlated with sensory disturbances. The cut-off values for the area and length of the tumor in the sagittal plane to predict paralysis were 243 mm2 and 20.1 mm, respectively. CONCLUSIONS: Preoperative paralysis in patients with spinal meningiomas was significantly associated with sagittal tumor size than with high tumor occupancy in the horizontal plane. Sensory disturbances were associated with high occupancy in the horizontal plane. Patients with spinal meningiomas > 20 mm in length or 243 mm2 in area in the sagittal plane are at risk of developing paralysis and could be considered for surgery even in the absence of paralysis.

Clinical Features and Surgical Outcomes of Lower Lumbar Osteoporotic Vertebral Collapse with Symptomatic Stenosis: A Surgical Strategy from a Multicenter Case Series.

STUDY DESIGN: A retrospective multicenter case series was conducted. PURPOSE: This study was designed to investigate the clinical features and surgical outcomes of lower lumbar osteoporotic vertebral collapse (LL-OVC) with symptomatic stenosis based on various surgical procedures and classify them using the newly developed collapse severity criteria. OVERVIEW OF LITERATURE: The surgical outcomes of LL-OVC with symptomatic stenosis remain unclear. METHODS: We investigated patients who underwent surgical intervention for LL-OVC (L3, L4, and/or L5) with symptomatic foraminal and/or central stenosis from eight spine centers. Only patients with a minimum follow-up duration of 1 year were included. We developed new criteria to grade vertebral collapse severity (grade 1, 0%-25%; grade 2, 25%-50%; grade 3, 50%-75%; and grade 4, 75%-100%). The clinical features and outcomes were compared based on the collapse grade and surgical procedures performed (i.e., decompression alone, posterior lateral fusion [PLF], lateral interbody fusion [LIF], posterior/transforaminal interbody fusion [PLIF/TLIF], or vertebral column resection [VCR]). RESULTS: In this study, 59 patients (average age, 77.4 years) were included. The average follow-up period was 24.6 months. The clinical outcome score (Japanese Orthopaedic Association score) was more favorable in the LIF and PLIF/TLIF groups than in the decompression alone, PLF, and VCR groups. The use of VCR was associated with a high rate of revision surgery (57.1%). No significant difference in clinical outcomes was observed between the collapse grades; however, grade 4 collapse was associated with a high rate of revision surgery (40.0%). CONCLUSIONS: When treating LL-OVC, appropriate instrumented reconstruction with rigid intervertebral stability is necessary. According to our newly developed criteria, LIF may be a surgical option for any collapse grade. The use of VCR for grade 4 collapse is associated with a high rate of revision.