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.

Interbody Cage Placement Without Plate Supplementation Adjacent to Plated Segments in Multilevel Anterior Cervical Decompression and Fusion.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To evaluate the clinical efficacy and safety of hybrid anterior cervical fixation, focusing on stand-alone segments. SUMMARY OF BACKGROUND DATA: In the treatment of multilevel cervical stenosis, the number of segments fixed using a plate is limited by placing an interbody cage without plate supplementation at one end of the surgical segment to reduce long plate-related problems. However, the stand-alone segment may experience cage extrusion, subsidence, cervical alignment deterioration, and nonunion. METHODS: Patients who underwent three-segment or four-segment fixation for cervical degenerative disease and completed one-year follow-up were included in this study. Patients were divided into two groups: a cranial group, with stand-alone segments located at the cranial end adjacent to plated segments, and a caudal group, with stand-alone segments located at the caudal end. Differences in radiographic outcomes between the groups were evaluated. Fusion was defined using dynamic radiographs or computed tomography. To identify factors associated with nonunion in stand-alone segments, multivariable logistic regression analyses were performed. To identify factors associated with cage subsidence, multiple regression analyses were performed. RESULTS: A total of 116 patients (mean age, 59±11 y; 72% male; mean fixed segments, 3.7±0.5 segments) were included in this study. No case showed cage extrusion or plate dislodgement. In stand-alone segments, the fusion rate was significantly lower in the caudal group than in the cranial group (76% vs. 93%, P =0.019). Change in the cervical sagittal vertical axis was worse in the caudal group than in the cranial group (2.7±12.3 mm vs. -2.7±8.1 mm, P =0.006). One caudal group patient required additional surgery because of nonunion at the stand-alone segment. Multivariable logistic regression indicated factors associated with nonunion included the location of the stand-alone segment (caudal end: OR 4.67, 95% CI, 1.29-16.90), larger pre-disk space range of motion (OR 1.15, 95% CI, 1.04-1.27), and lower preoperative disk space height (OR 0.57, 95% CI, 0.37-0.87). Multiple regression analysis indicated that higher cage height and lower pre-disk space height were associated with cage subsidence. CONCLUSION: Hybrid anterior cervical fixation with stand-alone interbody cage placement adjacent to plated segments may avoid long plate-related problems. Our results suggest that the cranial end of the construct may be more suitable for the stand-alone segment than the caudal end.

Risk Factors for Cage Migration Following Lateral Lumbar Interbody Fusion Combined With Posterior Instrumentation: A Multicenter Retrospective Study of 983 Cases.

STUDY DESIGN: A multicenter retrospective study. OBJECTIVE: This study aimed to elucidate the incidence and risk factors of lateral cage migration (LCM) after lateral lumbar interbody fusion (LLIF) combined with posterior instrumentation. SUMMARY OF BACKGROUND DATA: LLIF has recently become a widely accepted procedure for the treatment of lumbar degenerative diseases. Although LLIF complications include vascular, nerve, and abdominal organ injuries, few studies have identified specific risk factors for LCM after LLIF. MATERIALS AND METHODS: Between January 2015 and December 2020, 983 patients with lumbar degenerative diseases or osteoporotic vertebral fractures underwent LLIF combined with posterior instrumentation. The fusion sites were located within the lumbosacral lesions. LCM was defined as a change of >3 mm in the movement of the radiopaque marker on radiographs. The patients were classified into LCM and non-LCM groups. Medical records and preoperative radiographs were also reviewed. The 1:5 nearest-neighbor propensity score matching technique was used to compare both groups, and radiologic parameters, including preoperative disk height (DH), preoperative sagittal disk angle, disk geometry, height variance (cage height minus DH), and endplate injury, were analyzed to identify the factors influencing LCM incidence. RESULTS: There were 16 patients (1.6%) with LCM (10 men and 6 women; mean age 70.1 yr). The Cochran-Armitage trend test showed a linear trend toward an increased rating of LCM with an increasing number of fused segments ( P =0.003), and LCM occurred at the terminal cage-inserted disk level in all patients in the LCM group. After propensity-matched analysis, we identified high DH ( P <0.001), large sagittal disk angle ( P =0.009), round-type disk ( P =0.008), and undersized cage selection ( P <0.001) as risk factors for LCM. CONCLUSION: We identified risk factors for LCM after LLIF combined with posterior instrumentation. To avoid this complication, it is important to select the appropriate cage sizes and enhance posterior fixation for at-risk patients.

Association of two-staged surgery with systemic perioperative complications in lateral lumbar interbody fusion for adult spinal deformity: a propensity score-weighted study.

PURPOSE: Adult spinal deformity (ASD) surgery carries a higher risk of perioperative systemic complications. However, evidence for the effect of planned two-staged surgery on the incidence of perioperative systemic complications is scarce. Here, we evaluated the effect of two-staged surgery on perioperative complications following ASD surgery using lateral lumbar interbody fusion (LLIF). METHODS: The study was conducted under a retrospective multi-center cohort design. Data on 293 consecutive ASD patients (107 in the two-staged group and 186 in the one-day group) receiving corrective surgery using LLIF between 2012 and 2021 were collected. Clinical outcomes included occurrence of perioperative systemic complications, reoperation, and intraoperative complications, operation time, intraoperative blood loss, transfusion, and length of hospital stay. The analysis was conducted using propensity score (PS)-stabilized inverse probability treatment weighting to adjust for confounding factors. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated in a PS-weighted cohort. RESULTS: In this cohort, 19 (18.4%) patients in the two-staged group and 43 (23.1%) patients in the one-day group experienced any systemic perioperative complication within 30 days following ASD surgery. In the PS-weighted cohort, compared with the patients undergoing one-day surgery, no association with the risk of systemic perioperative complications was seen in patients undergoing two-staged surgery (PS-weighted OR 0.78, 95% CI 0.37-1.63; p = 0.51). CONCLUSION: Our study suggested that two-staged surgery was not associated with risk for perioperative systemic complications following ASD surgery using LLIF.

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.

[Analysis of Prognostic Factors Considering Absolute Lymphocyte Count of Metastatic Breast Cancer Patients with Eribulin Mesylate Therapy-A Retrospective Study in a Single Institution].

Recently, a study for eribulin mesylate(ERI), which is a useful drug for metastatic and recurrent breast cancer, reported that the absolute lymphocyte count(ALC)before administration is a useful prognostic factor. We retrospectively examined whether the results were reproducible in the patients with ERI. We examined the effect of ERI on the overall survival(OS)in 21 patients with HER2-negative metastatic and recurrent breast cancer who underwent treatment with ERI at our hospital. The clinical benefit ratio(CBR)was 57.1%. The median time to treatment failure(TTF)was 5.8 months and median OS was 19.9 months, showing a positive correlation between the TTF and OS. The factors that significantly prolonged the OS in univariate analysis were the TTF(<3 months vs ≥3 months, p<0.001), NLR(<3 vs ≥3, p=0.037), and ALC(<1,000/ µL vs ≥1,000/µL, p=0.008). In the multivariate analysis, TTF and ALC were the prognostic factors. The ERI outcome at our institution was good regardless of the subtype. The results of the multivariate analysis showed that TTF and ALC were factors that prolonged OS, and patients who received ERI for >3 months had good OS. Long-term administration of ERI was assumed to affect the immune microenvironment and prolong OS. Additionally, our data showed that the lymphocyte count before ERI administration is a simple and useful prognostic factor.

Reoperation for Misplaced Pedicle Screws: A Multicenter Retrospective Study.

STUDY DESIGN: A multicenter retrospective analysis. OBJECTIVE: This study aims to investigate reoperation of misplaced pedicle screws (MPSs) after posterior spinal fusion (PSF), focusing on neurological complications. SUMMARY OF BACKGROUND DATA: The management strategy for MPSs and the clinical results after reoperation are poorly defined. MATERIALS AND METHODS: Subjects were 10,754 patients (73,777 pedicle screws) who underwent PSF at 11 hospitals over 15 years. The total number of reoperations for MPS and patient clinical data were obtained from medical records at each hospital. RESULTS: The rate of reoperation for screw misplacement per screw was 0.17%. A total of 69 patients (mean age, 67.4±16.5 yr) underwent reoperation because of 82 MPS. Reasons for reoperation were neurological symptoms (58 patients), contact with vessels (5), suboptimal bone purchase (4), and misplacement recognized during operation (2). Neurological symptoms were the major reason for reoperation in cervical (5/5 screws, 100%) and lumbo-sacral (60/67 screws, 89.6%) regions. Contact with vessels was the major reason for reoperation in the thoracic spine (6/10 screws, 60.0%). We further evaluated 60 MPSs in the lumbo-sacrum necessitating reoperation because of neurological symptoms. The majority of MPSs necessitating reoperation were placed in the lower lumbar spine (43/60 screws, 71.7%). The mean pedicle breach tended to be larger in the incomplete recovery group than in the complete recovery group (6.8±2.4 vs . 5.9±2.2 mm, P =0.146), and the cutoff value resulting in incomplete resolution was 5.0 mm. Multivariate analysis revealed that medial-caudal breaches ( vs . medial breach, odds ratio: 25.8, 95% confidence interval: 2.58-258, P =0.0057) and sensory and motor disturbances ( vs . sensory only, odds ratio: 8.57, 95% confidence interval: 1.30-56.6, P =0.026) were significant factors for incomplete resolution of neurological symptoms. CONCLUSIONS: After reoperation, 70.1% of the patients achieved complete resolution of neurological symptoms. Factors associated with residual neurological symptoms included sensory and motor disturbance, medial-caudal breach, and larger pedicle breach (>5 mm).

A rare case of synchronous multiple primary malignancies of breast cancer and diffuse large B-cell lymphoma that responded to multidisciplinary treatment: a case report.

BACKGROUND: Multiple primary malignancies of breast cancer and diffuse large B-cell lymphoma (DLBCL) are rare. Here, we report a case of advanced breast cancer and DLBCL managed with multidisciplinary therapy preceded by surgery with a successful outcome. CASE PRESENTATION: During a medical examination, a 71-year-old woman was diagnosed with a right breast mass, enlarged lymph nodes throughout the body, and a splenic tumor. The results of the clinical examination and imaging were suggestive of widely spread breast cancer with lymph node metastasis and malignant lymphoma with systemic metastasis. The histological evaluation of the biopsied breast tissue revealed human epidermal growth factor receptor 2 (HER2)-positive breast cancer, whereas the histological evaluation of the excised inguinal lymph node revealed DLBCL. 18F-FDG PET/computed tomography was performed, and it was determined that both breast cancer and DLBCL were in an advanced stage. Thus, mastectomy was performed, and the axillary lymph nodes showed mixed metastasis of breast cancer and DLBCL. Soon after, the R-CHOP therapy was initiated (375-mg/m2 rituximab, 2-mg/m2 vincristine, 50-mg/m2 doxorubicin, 750-mg/m2 cyclophosphamide, and 125-mg methylprednisolone). After irradiation of the spleen, trastuzumab was administered for 1 year. CONCLUSIONS: We experienced a case of combined breast cancer and DLBCL, which was difficult to treat because both were in advanced stages. Thorough staging of the malignancy and discussion by a multidisciplinary team are necessary to determine the optimal treatment strategy.

Insufficient Recovery From C5 Palsy Following Anterior Cervical Decompression and Fusion.

STUDY DESIGN: Retrospective study. OBJECTIVE: To determine the risk factors for insufficient recovery from C5 palsy (C5P) following anterior cervical decompression and fusion (ADF). SUMMARY OF BACKGROUND DATA: Postoperative C5P is a frequent but unsolved complication following cervical decompression surgery. Although most patients gradually recover, some recover only partially. When we encounter new-onset C5P following ADF, the question that often arises is whether the palsy will sufficiently resolve. METHODS: We retrospectively reviewed consecutive patients who underwent ADF at our institution. We defined C5P as postoperative deterioration of deltoid muscle strength by two or more grades determined by manual muscle testing (MMT). We evaluated the following demographic data: patient factors, surgical factors, and radiological findings. C5P patients were divided into two groups: sufficient recovery (MMT grade≧4) and insufficient recovery (MMT grade < 4). Each parameter was compared between the two groups. RESULTS: Of 839 patients initially included in the study, 57 experienced new-onset C5P (6.8%). At the final follow-up (mean, 55 ±â€Š17 months), 41 patients experienced sufficient recovery, whereas 16 (28%) still exhibited insufficient recovery. Compared with the sufficient recovery group, patients with insufficient recovery exhibited a higher decompression combination score, a larger anterior shift in preoperative cervical sagittal balance, less lordosis of the pre- and postoperative C4/C5 segment, more frequent stenosis at the C3/C4 segment, lower deltoid strength at C5P onset, more frequent co-occurrence of biceps weakness, greater postoperative expansion of the dura mater, and more frequent presence of postoperative T2 high-intensity areas. Multivariate analysis revealed that co-occurrence of biceps muscle weakness, less lordosis at the preoperative C4/C5 segment, and postoperative expansion of the dura mater were independent predictors of insufficient recovery. CONCLUSION: The combination of unfavorable conditions, such as potential spinal cord disorder, cervical malalignment, and excessive expansion of the dura mater after corpectomy, predicts insufficient recovery from C5P.Level of Evidence: 4.

Giant Cell Tumor of Bone of the First Rib Successfully Treated with Combined Preoperative Denosumab Therapy and Surgery via a Transmanubrial Approach.

BACKGROUND Giant cell tumor of bone (GCTB) is a locally aggressive, intermediate tumor that rarely metastasizes. GCTB typically affects the ends of long bones and rarely involves the ribs. Curettage is typically the treatment of choice for GCTB in long bones. However, the optimal treatment of GCTB in ribs remains unclear. We report the case of a patient with asymptomatic GCTB of the first rib that was successfully treated with combined preoperative denosumab therapy and surgery via a transmanubrial approach without resection of the clavicle. CASE REPORT A healthy 27-year-old woman presented with a bone tumor involving the left first rib that was incidentally discovered on routine chest X-ray. Histological examination of core-needle biopsy specimens of the lesion led to a pathological diagnosis of GCTB. After preoperative denosumab treatment for 6 months, en bloc resection via a transmanubrial approach was performed. There were no serious postoperative complications. The patient remained free of symptoms and had no recurrence 4.5 years after surgery. CONCLUSIONS Compared with other ribs, masses located in the first rib can be challenging to treat surgically because of the clavicle and neighboring neurovascular structures. This report is the first to describe GCTB located on the anterior aspect of the first rib that was successfully treated with combined preoperative denosumab therapy and surgery via a transmanubrial approach, with no recurrence or functional impairment of the shoulder girdle.

Association Between C5 Palsy and the Anterior Decompression Procedures, Corpectomy and Discectomy.

STUDY DESIGN: This is a retrospective study. OBJECTIVE: The aim was to evaluate the influence of various decompression procedures on the incidence of C5 palsy (C5P). SUMMARY OF BACKGROUND DATA: C5P is a well-known but unsolved complication of cervical spine surgery. Among anterior cervical decompressive procedures, both corpectomy and discectomy are important surgical methods, whose effects on the incidence of C5P are unknown. METHODS: We retrospectively analyzed 818 patients (529 men; mean age: 59.2±11.6 y) who underwent anterior cervical decompression and fusion. The surgical choice to use corpectomy, discectomy, or hybrid decompression was based on standard treatment strategies depending on local compressive pathology and presenting clinical symptoms. We introduced an original "decompression combination score" as a means of quantifying the effects of the procedures on the development of C5P. The scores were based on the relative severity of various risk factors associated with the eventual development of C5P and were assigned as follows: C4 corpectomy, 1 point; C5 corpectomy, 1 point; C3 corpectomy successive to C4 corpectomy, 0.5 point; C6 or C7 corpectomy successive to C5 corpectomy, 0.5 point; C4/5 discectomy, 0.5 point; discectomy at another segment, 0 point. Each patient's decompression combination score was then comprised of the sum of these points. RESULTS: C5P occurred in 55 (47 men, mean age: 65.7±8.7 y) of the 818 (6.7%) patients. A larger number of operated disc segments was significantly associated with C5P. Higher decompression combination score was significantly associated with C5P. Multivariate analysis revealed that male sex, higher decompression combination score, and older age were significant risk factors. CONCLUSIONS: Corpectomy increased the incidence of C5P, while discectomy decreased the risk. The lower incidence of postoperative C5P after discectomy may be because of minimizing tethering effect to the C5 nerve root. As a preventive measure against C5P, corpectomy should be avoided, while discectomy is recommended as much as possible. LEVEL OF EVIDENCE: Levels of Evidence: Step IV-Oxford Center for Evidence-Based Medicine 2011.

Cranial Kyphotic Change After Multilevel Anterior Cervical Corpectomy and Fusion May Lead to Myelopathy Recurrence.

OBJECTIVE: To determine the characteristic alignment change in patients with myelopathy recurrence after multilevel anterior cervical corpectomy and fusion (m-ACCF). METHODS: We analyzed 52 patients who underwent m-ACCF, including 20 who underwent revision surgeries for myelopathy recurrence (R group) and 32 postoperative asymptomatic patients (A group). Classic alignment parameters (cervical lordosis angle, cervical sagittal vertical axis, and fusion area angle and length) and original alignment parameters (α-ß, ß-bone graft [BG], BG-γ, and γ-δ angles) were measured preoperatively, postoperatively, and at follow-up or before revision surgery. The difference in the amount of change in parameters between groups was analyzed. The relationship between distribution of restenotic lesions and characteristic alignment change in the R group was evaluated. RESULTS: Cervical lordosis angle, fusion area angle, and fusion area length in the R group significantly decreased postoperatively compared with the A group (P < 0.01, P < 0.01, and P = 0.04). Compared with the A group, α-ß and ß-BG angles in the R group significantly decreased (P < 0.01), indicating kyphotic change on the cranial side. BG-γ and γ-δ angles in the R group significantly increased (P < 0.01), indicating lordotic change in the caudal fused area. Restenotic lesions significantly increased on the cranial side in the R group (cranial side, 19 levels; caudal side, 5 levels; P < 0.01). CONCLUSIONS: In patients with myelopathy recurrence after m-ACCF, the cranial side has significant kyphosis and the caudal side has lordosis. Moreover, 79.2% of the restenotic lesions were significantly maldistributed on the cranial side. Surgeons should pay close attention to cranial kyphosis inducing myelopathy recurrence after m-ACCF.

Compensatory Mechanisms for Kyphotic Change in the Cervical Spine According to Alignment Analysis of the Cases after Anterior Cervical Corpectomy and Fusion.

BACKGROUND: Compensatory mechanisms for cervical kyphosis are unclear. Few alignment analyses have targeted ongoing cervical kyphosis and detailed the effects of compensatory alignment changes. METHODS: We analyzed the radiographic alignment parameters of 31 patients (21 men and 10 women) with postoperative kyphotic changes after anterior cervical corpectomy and fusion (ACCF) between 2006 and 2015. This analysis included lordotic angle of the fusion area, fusion area length, cervical lordosis angle (CL), O-C7 angle (O-C7a), and cervical sagittal vertical axis (cSVA) as basic parameters and occipito-C2 angle (O-C2a), adjacent cranial angle, adjacent caudal angle, and T1 slope as compensatory parameters at 2 time points after surgery. RESULTS: Alignment analysis revealed that CL was significantly decreased by 5.0 ± 7.7° (P < 0.01) and O-C7a was changed by only -0.2 ± 6.8° (P = 0.75). An inverse correlation was found between ΔCL and ΔO-C2a (ρ = -0.40), with a nearly 1:1 relationship in the scatter diagram. ΔT1 slope had no direct compensatory correlation with ΔCL (P = 0.28) but was strongly correlated with ΔcSVA (ρ = 0.78). The scatter diagram of ΔcSVA and ΔT1 slope showed compensatory relevance and a shifted point to its collapse as the T1 slope lost control of cSVA; thereafter, both parameters incessantly increased, and ΔT1 and ΔcSVA became positive. CONCLUSIONS: When CL decreased after ACCF, ΔO-C2 immediately compensated for the CL loss that could lead to failure to obtain horizontal gaze. If cSVA increased, Δcaudal adjacent angle and ΔT1 slope (extension below the kyphosis) compensated for the horizontal offset translation. The noncompensatory status (ΔcSVA and ΔT1 positive) may necessitate further correction surgery in which the caudal fused level is beyond T1.

Surgical strategies and outcomes for intradural lipomas over the past 20 years.

Intradural lipoma is an extremely rare spinal tumor. The boundary between the spinal cord and the lipoma is usually unclear, with adhesions being firm. Thus, total resection of the tumor is difficult and the neurological prognosis after total resection is poor. Information on the management of this type of tumor is scarce owing to the limited studies that have been conducted and the low sample sizes reported. Here, we report a case and provide a review of the literature on intradural lipomas over the past 20 years. In addition to describing our case, we reviewed reports published in Pubmed and CiNii. The demographic data of the patients included in these studies were extracted and the surgical procedures were assessed, along with their corresponding postoperative outcomes. There were 57 primary cases and 4 cases of recurrence. Among the primary cases, the neurological symptoms were persistent in 54 (95%) after surgery. The postoperative outcomes after excessive (>60% tumor resection) or total resection were significantly poor. In the recurrence cases, the mean period from initial surgery to recurrence was 11 years and all initial surgical procedures involved only partial resection surgery. This report is, to the best of our knowledge, the most exhaustive analysis of cases of intradural lipomas and recurrences. The optimal treatment for lipoma necessitates both partial resection and duraplasty.

Clinical and radiological features of spinal extradural arachnoid cysts: Valve-like mechanism involving the nerve root fiber as a possible cause of cyst expansion.

BACKGROUND: Although a valve-like mechanism has been proposed for expansion of spinal extradural arachnoid cysts (SEACs), the detailed mechanism remains unclear. Moreover, closure of the communication site is essential during surgery, but the method to identify the communication site remains unclear. The aim of this study was to determine the detailed mechanism of expanding SEACs through retrospective analysis of SEAC cases undergoing surgery and to elucidate the characteristics of the communication sites. METHODS: The authors retrospectively evaluated 12 patients with SEACs who underwent surgery between 2000 and 2014 and analyzed their perioperative findings. RESULTS: Dural defects were detected in 11 out of 12 patients, and a valve-like mechanism was observed in 7 patients, wherein a nerve root fiber moved back and forth through the dural defect along with the flow of cerebrospinal fluid (CSF) between the intradural space and the extradural arachnoid cysts. The dural defect was located at the thoracolumbar junction in 7 patients, below the distal end of the bridging ossification in 2, at the level of vertebral wedge deformity in 2, and at the level of disc herniation in 1. CONCLUSIONS: A valve-like mechanism was observed in 7 of the 12 patients, which suggests that it could serve as a mechanism of SEAC formation. The communication sites were variously located at the end of ossification in patients with diffuse idiopathic skeletal hyperostosis (DISH), wedge deformity of the vertebral body, or disc herniation, indicating the contribution of mechanical stress to SEAC formation.

Catastrophic Dropped Head Syndrome Requiring Multiple Reconstruction Surgeries after Cervical Laminoplasty.

INTRODUCTION: Dropped head syndrome (DHS) after cervical laminoplasty (LAMP) is a rare complication, and no etiologies or surgical strategies have been reported. We present a patient who developed catastrophic DHS after LAMP despite having preoperative cervical lordosis that is known to be suitable for LAMP. We describe a hypothesis concerning the possible mechanism responsible for the DHS and a surgical strategy for relieving it. CASE REPORT: A 76-year-old woman underwent LAMP for cervical spondylotic myelopathy. She achieved satisfactory improvement of neurological symptoms immediately after surgery. However, her neurological symptoms began to gradually deteriorate. She exhibited a dropped head and complained of difficulty maintaining horizontal gaze. Postoperative images showed a focal cervical kyphotic deformity causing anterior shift of the head, and recurrence of spinal cord compression was observed. She underwent additional surgeries for three times, but none of them restored her to baseline status. Retrospectively, the preoperative loading axis of the head existed anteriorly, and she also had a high T1 slope because of rigid thoracic kyphosis. Her preoperative hyper cervical lordosis was compensation for the global spinal malalignment. After LAMP, in accordance with decreases in her cervical lordosis, her head shifted anteriorly. The abnormal lever arm acting on the neck put further stress on the neck extensors, and the overstretched neck extensors possibly no longer generated enough power to raise the head. Uncompensated very high T1 slope because of marked thoracic kyphosis plus invasion of the posterior extensor mechanism by LAMP may have contributed to her catastrophic DHS development. CONCLUSIONS: In the treatment of cervical myelopathy, posterior decompression alone should be applied carefully to elderly patients with cervical sagittal imbalance even if they have apparent cervical lordosis. Once DHS occurs because of cervical sagittal imbalance, normalization of global spinal balance through corrective osteotomy may be indispensable for a successful outcome.

Pedicle Screw Fluid Sign: An Indication on Magnetic Resonance Imaging of a Deep Infection After Posterior Spinal Instrumentation.

STUDY DESIGN: A single-center case-referent study. OBJECTIVE: To assess whether the "pedicle screw (PS) fluid sign" on magnetic resonance imaging (MRI) can be used to diagnose deep surgical site infection (SSI) after posterior spinal instrumentation (PSI). SUMMARY OF BACKGROUND DATA: MRI is a useful tool for the early diagnosis of a deep SSI. However, the diagnosis is frequently difficult with feverish patients with clear wounds after PSI because of artifacts from the metallic implants. There are no reports on MRI findings that are specific to a deep SSI after PSI. We found that fluid collection outside the head of the PS on an axial MRI scan (PS fluid sign) strongly suggested the possibility of an abscess. METHODS: The SSI group comprised 17 patients with a deep SSI after posterior lumbar spinal instrumentation who had undergone an MRI examination at the onset of the SSI. The non-SSI group comprised 64 patients who had undergone posterior lumbar spinal instrumentation who did not develop an SSI and had an MRI examination within 4 weeks after surgery. The frequency of a positive PS fluid sign was compared between both groups. RESULTS: The PS fluid sign had a sensitivity of 88.2%, specificity of 89.1%, positive predictive value of 68.1%, and negative predictive value of 96.6%. The 2 patients with a false-negative PS fluid sign in the SSI group had an infection at the disk into which the interbody cage had been inserted. Three of the 7 patients with a false-positive PS fluid sign in the non-SSI group had a dural tear during surgery. CONCLUSIONS: The PS fluid sign is a valuable tool for the early diagnosis of a deep SSI. The PS fluid sign is especially useful for diagnosing a deep SSI in difficult cases, such as feverish patients without wound discharge.

Surgical results and complications of anterior decompression and fusion as a revision surgery after initial posterior surgery for cervical myelopathy due to ossification of the posterior longitudinal ligament.

OBJECTIVE Ossification of the posterior longitudinal ligament (OPLL) is a progressive disease. An anterior cervical decompression and fusion (ACDF) procedure for cervical OPLL is theoretically feasible, as the lesion exists anteriorly; however, such a procedure is considered technically demanding and is associated with serious complications. Cervical laminoplasty is reportedly an effective alternative procedure with few complications; it is recognized as a comparatively safe procedure, and has been widely used as an initial surgery for cervical OPLL. After posterior surgery, some patients require revision surgery because of late neurological deterioration due to kyphotic changes in cervical alignment or OPLL progression. Here, the authors retrospectively investigated the surgical results and complications of revision ACDF after initial posterior surgery for OPLL. METHODS This was a single-center, retrospective study. Between 2006 and 2013, 19 consecutive patients with cervical OPLL who underwent revision ACDF at the authors' institution after initial posterior surgery were evaluated. The mean age at the time of revision ACDF was 66 ± 7 years (± SD; range 53-78 years). The mean interval between initial posterior surgery and revision ACDF was 63 ± 53 months (range 3-235 months). RESULTS The mean follow-up period after revision ACDF was 41 ± 26 months (range 24-108 months). Before revision ACDF, the mean maximum thickness of the ossified posterior longitudinal ligament was 7.2 ± 1.5 mm (range 5-10 mm), and the mean C2-7 angle was 1.3° ± 14° (range -40° to 24°). The K-line was plus (OPLL did not exceed the K-line) in 8 patients and minus in 11 (OPLL exceeded the K-line). The mean Japanese Orthopaedic Association score improved from 10 ± 3 (range 3-15) before revision ACDF to 11 ± 4 (range 4-15) at the last follow-up, and the mean improvement rate was 18% ± 18% (range 0%-60%). A total of 16 surgery-related complications developed in 12 patients (63%). The main complication was an intraoperative CSF leak in 8 patients (42%). Neurological function worsened in 5 patients (26%). The deterioration was due to spinal cord herniation through a defective dura mater in 1 patient, unidentified in 1 patient, and C-5 palsy that gradually recovered in 3 patients. Reintubation, delirium, and hoarseness were observed in 1 patient each (5%). No patient required reoperation for reconstruction failure, and all patients eventually had a solid bony fusion. CONCLUSIONS ACDF as revision surgery after initial posterior surgery for cervical myelopathy due to OPLL is associated with a high incidence of intraoperative CSF leakage and an extremely low improvement rate. The authors think that while the use of revision ACDF must be limited, it is indispensable in special cases, such as progressing myelopathy following posterior surgery due to a very large beak-type OPLL that exceeds the K-line. Postoperative OPLL progression and/or kyphotic changes can possibly cause later neurological deterioration. Fusion should be recommended at the initial surgery for many cases of cervical OPLL to prevent such a challenging revision surgery.

Lumbar Spinal Surgery in Patients With Parkinson Disease: A Multicenter Retrospective Study.

STUDY DESIGN: A multicenter, retrospective study. OBJECTIVE: To identify the factors that affect surgery-related complications and to clarify the surgical strategy for treating lumbar disorders in Parkinson disease (PD). SUMMARY OF BACKGROUND DATA: Previous studies have reported a high complication rate for spinal surgery in patients with PD. Because of the limited number of studies, there are no guidelines for spinal surgery for PD patients. METHODS: We retrospectively reviewed the records for 67 PD patients who underwent lumbar spinal surgery. The patients were divided into 3 groups: 12 patients underwent laminectomy (Laminectomy), 24 underwent fusion surgery (Fusion) for lumbar canal stenosis, and 31 underwent corrective surgery for spinal deformity (Deformity). We assessed surgery-related complications in each group. The Cox proportional hazards model was used to identify the factors that predicted surgical failure. RESULTS: The percentages of patients who experienced failure of the initial surgery were 33.3% in the Laminectomy group, 45.8% in the Fusion group, and 67.7% in the Deformity group. The rates of implant failure were high in the Fusion and Deformity groups (33.3% and 38.7%, respectively). The Deformity group had a high rate of postoperative fracture (41.9%). These complications occurred at the most caudal site within a year after surgery and resulted in progression of kyphotic deformity. Multivariate analysis revealed that preoperative lumbar lordosis angle (LL) (per -1 degree) was associated with a failure of the initial surgery (hazard ratio, 1.024; 95% confidence interval, 1.008-1.04; P=0.003). CONCLUSIONS: We have demonstrated that a small preoperative LL increases the risk for failure of the initial surgery. Attaining and maintaining the proper lumbar lordosis with rigid fixation may be necessary in PD patients with a small preoperative LL.