Dural rupture and subsequent spinal cord herniation due to closed wound suction drainage after spinal surgery.

Closed wound suction drains are commonly used in spinal surgery. Severe neurological complications related to their use are rare. Here, we report a case of a dural rupture and subsequent spinal cord herniation related to the use of closed suction drains after posterior decompression and fixation surgery for spinal metastasis.

Analysis of postoperative dysphagia after anterior cervical decompression and fusion.

Purpose: To investigate the incidence and risk factors of postoperative dysphagia after anterior cervical decompression and fusion (ACDF) in terms of demographic, procedural and anaesthetic perspectives.Materials and methods: Medical records and radiologic data of patients who underwent anterior cervical surgery performed by two surgeons in a single centre between January 2012 and December 2015 were retrospectively analysed. Patients with spinal tumours, infective spondylitis and traumatic cervical pathologies were excluded. Patients with preoperative dysphagia and previous history of anterior cervical surgery were also excluded. Finally, 127 patients were enrolled. Bazaz dysphagia score was used for the diagnosis of postoperative dysphagia.Results: The incidence of postoperative dysphagia was 10.2% at six weeks after ACDF. Nine patients showed mild dysphagia that fully recovered at three months after ACDF. Four patients showed moderate dysphagia that also recovered fully at six months after surgery. The incidence of postoperative dysphagia increased significantly in cases of C4 or C5 level involvements. Age, sex, hypertension, body mass index, postoperative soft tissue swelling, intubation difficulty and intubation tools were not significant risk factors of ACDF. Diabetes mellitus, two surgical levels, the use of plate, long anaesthetic and operative time and large intubation tube size were causative factors of postoperative dysphagia in multivariable analysis (p < 0.05).Conclusions: The incidence of postoperative dysphagia after ACDF was relatively low, and the prognosis was good.

Effects of Zeolite Supports on the Production of Fuel-Range Hydrocarbons in the Hydrotreatment of Various Vegetable Oils with Platinum-Based Catalysts.

The effects of catalyst supports on catalyst performance in the hydrotreatment of vegetable oils (to produce fuel-range hydrocarbons such as gasoline, jet fuel, and diesel) were investigated, using three types of zeolites (ZSM-5, HY, and zeolite-beta (BEA)) that differ in their silica/alumina ratios. Structural characterization of the catalysts was performed using ICP, XRD, BET, TEM, and NH3-TPD. Catalytic tests were carried out in a fixed-bed reaction system at 400 °C and 50 bar. In the hydrotreatment of soybean oil, higher conversions into liquid hydrocarbons and fuel-range hydrocarbons were found when supports with lower Si/Al2 ratios were used. Specifically, Pt/BEA (Si/Al2 = 25) produced the highest conversion into liquid products (72%) and the highest selectivity for hydrocarbons in the jet fuel (46%) and diesel (51%) fuels. A Pt loading amount of 3 wt% in this catalyst gave the best catalytic performance because of the optimal balance between acidic and metallic sites. Finally, the kinds of vegetable oils in the hydrotreatment performance over Pt/BEA (Si/Al2 = 25) affected the order; waste-cooking oil > jatropha oil > soybean oil.

Selective Ring Opening of 1-Methylnaphthalene Over NiW-Supported Catalyst Using Dealuminated Beta Zeolite.

Nanoporous Beta zeolite was dealuminated by weak acid treatment for reducing the acidity. Bi-functional catalysts were prepared using commercial Beta zeolites and the dealuminated zeolites for acidic function, NiW for metallic function. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction has been investigated using the prepared bi-functional catalysts with different acidity in fixed bed reaction system. The dealuminated Beta zeolites, which crystal structure and nanoporosity were maintained, showed the higher SiO2/Al2O3 ratio and smaller acidity than their original zeolite. NiW-supported catalyst using the dealuminated Beta zeolite with SiO2/Al203 mole ratio of 55 showed the highest performance for the selective ring opening. The acidity of catalyst seemed to play an important role as active sites for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. The acidity of Beta zeolite could be controlled by the acid treatment and the catalyst with the optimum acidity for the selective ring opening could be prepared.

The Effect of K and Acidity of NiW-Loaded HY Zeolite Catalyst for Selective Ring Opening of 1-Methylnaphthalene.

Bi-functional catalysts were prepared using HY zeolites with various SiO2/Al2O3 ratios for acidic function, NiW for metallic function, and K for acidity control. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction was investigated using the prepared bi-functional catalysts with different levels of acidity in a fixed bed reactor system. In NiW/HY catalysts without K addition, the acidity decreased with the SiO2/Al2O3 mole ratio of the HY zeolite. Ni1.1W1.1/HY(12) catalyst showed the highest acidity but slightly lower yields for the selective ring opening than Ni1.1W1.1/HY(30) catalyst. The acidity of the catalyst seemed to play an important role as the active site for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. Catalyst acidity could be controlled between Ni1.1W1.1/HY(12) and Ni1.1W1.1/HY(30) by adding a moderate amount of K to Ni1.1W1.1/HY(12) catalyst. K0.3Ni1.1W1.1/HY(12) catalyst should have the optimum acidity for the selective ring opening. The addition of a moderate amount of K to the NiW/HY catalyst must improve the catalytic performance due to the optimization of catalyst acidity.

Long-term recurrence rates after the removal of spinal meningiomas in relation to Simpson grades.

PURPOSE: Simpson grade II removal (coagulation of the dural attachment after gross total removal) of spinal meningioma is considered an acceptable alternative, but increased recurrence after more than 10 years has been reported. More attention must be paid to the long-term surgical outcomes after Simpson grade II removal. METHODS: A retrospective review was performed for 20 patients (M:F = 5:15; age, 59 ± 9 years) with Simpson grade II removal (mean follow-up period, 12.9 years; range 10.0-17.5). Magnetic resonance (MR) imaging was conducted in 17 patients at 88 ± 52 months (range 12-157). During the same period, Simpson grade I removal (removal of the dural origin) was performed in 21 patients (follow-up, 89 ± 87 months; range 9-316). Radiological recurrence was defined as a visible tumor on a follow-up MR image, and clinical tumor recurrence was defined as the recurrence of symptoms. RESULTS: At the final follow-up, neurological symptoms had improved in 16/20 patients and remained stable in 4/20. A recurrent tumor was detected in one patient due to increased back pain at 92 months postoperative, but the symptom was stable without surgery until the last follow-up (124 months). The radiological and clinical recurrence-free survival periods were 150 ± 7 months (95 % CI 136-163) and 204 ± 6 months (95 % CI 193-215), respectively. There was no recurrence after Simpson grade I removal, whereas neurological deterioration occurred in two patients after surgery. CONCLUSIONS: Simpson grade II removal may be an alternative option if the risk of complications with Simpson grade I removal is expected to be high.

Highly unstable cervical spine injury in an infant: a case report.

UNLABELLED: Although the rate of surgical intervention for pediatric cervical spine injuries has risen, none of these instrumentation techniques has been reported in children less than 1 year of age. Additional consideration with placement of wires or cables is not safe because of the presence of cartilaginous bone and poor bone strength. The authors report a technique of internal fixation without fusion using nonabsorbable synthetic suture in an infant with unstable cervical injury. METHODS: A 5-month-old girl was transported to emergency department and computed tomography showed severe distraction injury at the C6-7 level with total disruption of the facet joints bilaterally. To improve her general condition, she was placed in a customized occipito-cervical brace until surgical stabilization could be performed. After 1 month, surgical fixation was performed. After removing all soft tissues at the appropriate level, a hole was made in the center of the superior articular process of C6. A nonabsorbable suture (2-0 Ethibond; Ethicon, Somerville, NJ, USA) was passed from the superior articular process to the facet joint. The suture was passed into the spinous process of the lower level, and it was progressively tightened and radiographs were taken until anatomic reduction was achieved. RESULTS: After surgery, solid fusion was achieved. She was able to sit up in a stroller after 6 months. CONCLUSION: As surgical treatment of pediatric cervical spine injuries is unsuitable for infants, the Ethibond sutures are strong enough to hold and stabilize the spine. This suturing technique can be used as an alternative treatment for cervical injury in infants.

Synovial sarcoma of the spine: a case involving paraspinal muscle with extensive calcification and the surgical consideration in treatment.

INTRODUCTION: Synovial sarcoma is a rare malignant tumor of the spine. This tumor may present as a painless mass of the spine or slowly enlarge, causing pain or neurologic deficits. As it is difficult to differentiate this lesion from other soft tissue tumors, synovial sarcoma requires histologic confirmation for definite diagnosis. Thus, the treatment strategy is often planned in the final step depending on the pathologic results. Despite its rare incidence, a few cases of primary or metastatic synovial sarcoma involving the spinal cord, foramen, vertebral body, or paraspinal muscles have been reported in the literature. MATERIALS AND METHODS: We present the case of a 29-year-old man with a synovial sarcoma in the paraspinal muscle of the cervical spine. The patient was evaluated radiologically and histologically. Plain radiography, computed tomography, and magnetic resonance imaging were performed as part of the preoperative workup, and immunohistochemical and cytogenetic studies were additionally performed to identify the histologic features of the tumor. The patient underwent marginal resection followed by adjuvant radiation therapy. The patient has been followed up for 2 years. CONCLUSIONS: This article highlights the features of synovial sarcoma of the spine via a comprehensive review. Synovial sarcoma of the spine is uncommon, but it is a challenging issue in both diagnostic and therapeutic aspects. The currently available evidence suggests the use of a multidisciplinary approach in the treatment of synovial sarcoma, which includes complete resection and radiation therapy.

Analysis of the predictive role and new proposal for surgical strategies based on the modified Tomita and Tokuhashi scoring systems for spinal metastasis.

BACKGROUND: We sought to identify preoperative factors significantly correlated with survival. We also aimed to evaluate the validity of the prognostic scores in the Tomita and Tokuhashi systems and discuss several aspects to improve the predictive accuracy of these systems. Moreover, we suggest modified criteria for selecting treatment strategies. METHODS: In total, the outcomes of 112 patients with spinal metastasis who underwent surgery between January 2006 and June 2011 were retrospectively reviewed. The validity of the prognostic scores was assessed on the basis of their correlation with survival. For various primary malignancies, new scoring criteria were applied in each system according to the survival results obtained in this study. Each revised scoring system was adjusted with a similar principle of scoring as described previously. Patient survival according to each preoperative factor was analyzed by the Kaplan-Meier method. The predictive value of each scoring system was evaluated by the log-rank test and Cox regression analysis. RESULTS: The interval from the diagnosis of the primary malignancy to that of spinal metastasis (p = 0.023) and the interval from the diagnosis of spinal metastasis to surgery (p = 0.039) were significantly correlated with survival. Regarding Tokuhashi scores, the correlation coefficient was 0.790 before adjustment (p = 0.001) and 0.853 after adjustment (p < 0.001). For Tomita scores, the correlation coefficient was -0.994 (p < 0.001) both before and after adjustment. CONCLUSIONS: Tomita scores more accurately predicted survival than Tokuhashi scores. It is helpful to evaluate both scoring systems with adjustment for primary malignancy depending on the clinical setting. Patients with Tomita scores less than or equal to 8 and Tokuhashi scores greater than or equal to 6 are recommended to undergo surgical management.

Clinical and radiographic analysis of c5 palsy after anterior cervical decompression and fusion for cervical degenerative disease.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To present the cases of 6 patients who developed C5 palsy after anterior decompression and discuss the mechanism of C5 palsy development, especially with respect to radiographic change. SUMMARY OF BACKGROUND DATA: C5 palsy has been reported to be a major complication of both anterior and posterior decompression procedures. Although several mechanisms of injury have been proposed, few reports have been issued on C5 palsy after anterior decompression surgery. METHODS: A retrospective medical record review was performed on 134 patients who underwent anterior decompression and fusion in our hospital from 2008 to 2011. C5 paralysis was defined as deterioration in muscle power of the deltoid or biceps brachii by at least 1 grade by manual muscle testing. Clinical features and radiologic parameters were evaluated to identify predisposing factors. RESULTS: Six patients (4.3%) suffered postoperative paralysis in the upper extremities (C5 radiculopathy). C5 palsy did not occur in 30 patients with radiculopathy. Excluding patients with cervical radiculopathy, the rate of C5 palsies was 5.8% for myelopathy patients. Three of 76 (3.95'%) cervical spondylotic myelopathy cases, one of 6 (16.7%) cervical spondylotic radiculomyelopathy patients, and 2 of 22 (9%) patients with ossification of the posterior longitudinal ligament showed C5 palsy. In 2 of the 6, C5 palsy developed after anterior cervical corpectomy, in 3 patients after anterior cervical discectomy and plate fusion, and in 1 after a standalone cage. Two patients underwent reoperation for foraminal decompression. Of the 4 treated conservatively, 3 fully recovered and the other almost fully improved (grade 4). Of 2 patients treated surgically, 1 showed full improvements. The other had no improvement. Radiographic measurements of these 6 patients showed that lordosis at operated segments increased postoperatively (mean, 6 degrees), and that overall sagittal alignments of the cervical spine (C3-C7) also increased (mean, 8.2 degrees). CONCLUSIONS: This study suggests that improved lordosis of the cervical spinal column can result in traction injury to the spinal cord and C5 nerve roots and that reoperation does not always produce good results. Methods of preventing and treating C5 palsy after anterior decompression and fusion require more evaluation.

Development of a novel prediction model for differential diagnosis between spinal myxopapillary ependymoma and schwannoma.

Spinal myxopapillary ependymoma (MPE) and schwannoma represent clinically distinct intradural extramedullary tumors, albeit with shared and overlapping magnetic resonance imaging (MRI) characteristics. We aimed to identify significant MRI features that can differentiate between MPE and schwannoma and develop a novel prediction model using these features. In this study, 77 patients with MPE (n = 24) or schwannoma (n = 53) who underwent preoperative MRI and surgical removal between January 2012 and December 2022 were included. MRI features, including intratumoral T2 dark signals, subarachnoid hemorrhage (SAH), leptomeningeal seeding, and enhancement patterns, were analyzed. Logistic regression analysis was conducted to distinguish between MPE and schwannomas based on MRI parameters, and a prediction model was developed using significant MRI parameters. The model was validated internally using a stratified tenfold cross-validation. The area under the curve (AUC) was calculated based on the receiver operating characteristic curve analysis. MPEs had a significantly larger mean size (p = 0.0035), higher frequency of intratumoral T2 dark signals (p = 0.0021), associated SAH (p = 0.0377), and leptomeningeal seeding (p = 0.0377). Focal and diffuse heterogeneous enhancement patterns were significantly more common in MPEs (p = 0.0049 and 0.0038, respectively). Multivariable analyses showed that intratumoral T2 dark signal (p = 0.0439) and focal (p = 0.0029) and diffuse enhancement patterns (p = 0.0398) were independent factors. The prediction model showed an AUC of 0.9204 (95% CI 0.8532-0.9876) and the average AUC for internal validation was 0.9210 (95% CI 0.9160-0.9270). MRI provides useful data for differentiating spinal MPEs from schwannomas. The prediction model developed based on the MRI features demonstrated excellent discriminatory performance.

The Clinical Outcomes of Cervical Spine Chordoma: A Nationwide Multicenter Retrospective Study.

OBJECTIVE: Chordoma, a rare malignant tumor originating from embryonal notochord remnants, exhibits high resistance to conventional treatments, making surgical resection imperative. However, the factors influencing prognosis specifically for cervical spine chordoma have not been clearly identified. We investigate the prognosis of cervical spine chordoma with factors influential in a nationwide multicenter retrospective study. METHODS: This study included all patients diagnosed with cervical spine chordoma at 7 tertiary referral centers from January 1998 to March 2023, excluding those with clivus and thoracic spine chordomas extending into the cervical spine. Local recurrence (LR) was identified through follow-up magnetic resonance imaging, either as reappearance in completely resected tumors or regrowth in residual tumors. The study assessed LR and overall survival, analyzing factors influencing LR and death. RESULTS: Forty-five patients with cervical spine chordoma had a mean age of 46.4 years. Over a median follow-up of 52 months, LR and distant metastasis were observed in 21 (46.7%) and 4 patients (8.9%), respectively, and 16 patients (36%) were confirmed dead. The 5-year and 10-year cumulative LR rates were 51.3% and 60%, respectively, while the 5-year and 10-year survival rates were 82% and 53%. Age was the only significant factor affecting mortality (hazard ratio, 1.04; 95% confidence interval, 1.04-1.07; p=0.015). Notably, the degree of resection and adjuvant therapy did not statistically significantly impact local tumor control and mortality. CONCLUSION: This study, the largest multicenter retrospective analysis of cervical spine chordoma in Korea, identified age as the only factor significantly affecting patient survival.

The fate of spinal schwannomas following subtotal resection: a retrospective multicenter study by the Korea spinal oncology research group.

The fate of residual spinal schwannomas needs to be estimated in order to plan further management after subtotal removal. Our aim was to evaluate the growth rate of residual spinal schwannomas and compare results in regrowth and no regrowth groups by using data collected from the Korea Spinal Oncology Research Group database. From January 1989 to August 2011, 27 patients with residual spinal schwannomas were selected. Patients with at least two follow-up magnetic resonance image (MRI) studies after subtotal resection were included. The mean period of MRI follow-up was 62.4 months. A tumor size increase of over 2 mm in the maximal diameter was considered indicative of regrowth. Age, sex, size at initial diagnosis, postoperative tumor size, and Ki-67 labeling index were compared between regrowth and no regrowth groups. Eight residual schwannomas regrew (29.6 %), and 19 (70.4 %) did not regrow. Average growth rate of the regrowing tumors was 1.0 ± 4.4 mm/year. The mean percentage increase in tumor size during follow-up was 10.0 ± 28.8 %. The Ki-67 labeling indices were significantly different between regrowth and no regrowth groups (P = 0.014). Two patients underwent a revision operation for significant tumor regrowth. Nineteen cases (70.4 %) among 27 residual spinal schwannomas did not regrow significantly, but further surgical treatments were necessary in 2 patients due to significant regrowth. The Ki-67 labeling index was higher in the regrowth group. Earlier follow-up MRI is recommended for patients whose tumors have higher Ki-67.

Comparison of surgical outcomes after cervical laminoplasty: open-door technique versus French-door technique.

STUDY DESIGN: A retrospective case series. OBJECTIVE: To compare the surgical outcomes of open-door and French-door cervical laminoplasty for decompressing multilevel cervical spinal cord compressions. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty is an effective method for decompressing multilevel cervical spinal cord compressions. Laminoplasty is usually classified as an open-door or French-door technique, but it is still unclear whether laminoplasty affects cervical alignment and clinical outcomes. METHODS: Fifty-one patients underwent cervical laminoplasty over a 2-year period for cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament, or for a mixed-type condition. The following criteria were evaluated and compared retrospectively for open-door laminoplasty (group A) and French-door laminoplasty (group B): Nurick grades, Japanese Orthopedic Association (JOA) scores, neck disability index, and visual analog scale scores for axial neck pain and radiating pain. During radiologic evaluations, changes in cervical lordotic angles and range of motion were measured at C2-C7. RESULTS: Postoperatively, radiating pain improved significantly in both groups (P<0.05), but axial neck pain was more severe in both groups at last follow-up than preoperatively (P>0.05). Mean neurological improvement was 12.5% according to Nurick grades and 28% according to JOA scores in all study subjects. In particular, the mean Nurick grades showed significant improvement in group A (P<0.05), and the recovery rate was higher in group A than in group B according to Nurick grades (23.5% vs. 6.3%; P<0.05) and JOA scores (44.4% vs. 13%; P<0.05). In contrast, radiologically, cervical lordotic angle and range of motion were more significantly decreased in group B (P<0.05). CONCLUSIONS: Although open-door and French-door laminoplasty techniques were found to be effective for treating cervical compressive myelopathy, the open-door technique seems to be superior with respect to clinical and radiologic outcomes.

Long-term Follow-up Results of Reconstructive Laminoplasty With L-shaped Leibinger Mini-plate for Posterior Approach in the Treatment of Intraspinal Tumor Surgery.

OBJECTIVE: Laminoplasty using mini-plates is one of the most common surgical techniques in surgery for intraspinal pathologies. However, limited are present in the literature. The aim of this study was to determine its long-term clinical and radiologic outcome, specifically using an L-shaped mini-plate. METHODS: Patients who underwent surgery for spinal intradural pathology from January 2008 to December 2019 were retrospectively reviewed. Those who received laminoplasty using the Leibinger mini-plate and were followed for more than 2 years were included. Patient demographics and clinical and radiographic data were reviewed and analyzed. A total of 117 patients (male:female = 47:70; mean age 50.9 years, range 16-92 years) were included, and mean follow-up period was 50.3 months (range 24-151 months). RESULTS: The most common pathology was schwannoma (n = 66, 56.4%) followed by meningioma (n = 30, 25.6%). Gross total resection was achieved in 82.9% (n = 97). Clinical outcomes at last follow-up were mostly good and excellent (n = 95, 81.2%). Computed tomography at the postoperative 1-year follow-up were available in 32 patients (27.4%) and the overall fusion rate was 89.3% (50 of 56 laminae). The fusion rate was significantly lower in the cervical spine compared to other locations (50% vs. thoracic [100%], lumbar [85.7%], P < 0.002). No displacement of laminae or postoperative spinal deformity were observed throughout the follow-up. CONCLUSIONS: Laminoplasty using L-shape Leibinger mini-plates had an 89.3% fusion rate, and no displacement of the re-attached laminae was observed. We think it is a safe and feasible option in surgeries for intraspinal pathologies.

Impact on Spine Surgery during the First Two Years of COVID-19 Pandemic: A Nationwide Study in South Korea.

Since December 2019, the novel coronavirus (COVID-19) has infected people worldwide. Owing to its rapid spread, elective surgeries, including spine surgery, have been re-scheduled. We analyzed nationwide data to investigate changes in the volume of spine surgery during the first two years of the pandemic. Nationwide data from January 2016 to December 2021 were obtained. We compared the total number of patients who underwent spine surgery and related medical expenses before and during the COVID-19 pandemic. In February and September, the number of patients was significantly smaller compared to January and August, respectively. Despite the pandemic, the proportion of patients undergoing spine surgery for degenerative diseases in 2021 was the highest. In contrast, the proportions of patients undergoing spine surgery for tumors showed a continuous decrease from 2019 to 2021. Although the number of spine surgeries performed at tertiary hospitals was lowest in 2020, it was not significantly smaller than that in 2019.The number of patients who underwent spine surgery in March 2020, during the first outbreak, decreased compared to the previous month, which differed from the trend observed in the pre-COVID-19 period. However, as the pandemic continues, the impact of COVID-19 on spine surgery has become less evident.

Revisiting En Bloc Resection Versus Piecemeal Resection for the Treatment of Giant Cell Tumor of the Spine.

OBJECTIVE: Surgery for spinal giant cell tumors (GCTs) is challenging because these tumors often exhibit a poor clinical course owing to their locally aggressive features. This study aimed to investigate the prognostic factors of GCT recurrence in the spine by focusing on surgical factors. METHODS: We retrospectively reviewed patients who underwent surgery for spinal GCTs between January 2005 and December 2016. Using the Kaplan-Meier method, surgical variables were evaluated for disease-free survival (DFS). Since tumor violation may occur at the pedicle during en bloc resection of the spine, it was further analyzed as a separate variable. Multivariate Cox proportional hazard regression analysis was performed for other clinical and radiographic variables. A total of 28 patients (male:female = 8:20) were included. The mean follow-up period was 90.5 months (range, 15-184 months). RESULTS: Among the 28 patients, gross total resection (GTR) was the most important factor for DFS (P = 0.001). Any form of tumor violation was also correlated with DFS (P = 0.049); however, use of en bloc resection technique did not show a significant DFS gain compared to piecemeal resection (P = 0.218). In the patient group that achieved GTR, the mode of resection was not a significant factor for DFS (P = 0.959). In the multivariate analysis, the extent of resection was the only significant variable that affected DFS (P = 0.016). CONCLUSIONS: Conflicting results on tumor violation from univariate and multivariate analyses suggest that GTR without tumor violation should be the treatment goal for spinal GCTs. However, when tumor violation is unavoidable, it would be important to prioritize GTR over adhering to en bloc resection.

Uncovertebral hypertrophy is a significant risk factor for the occurrence of heterotopic ossification after cervical disc replacement: survivorship analysis of Bryan disc for single-level cervical arthroplasty.

OBJECTIVES: The purpose of this study is to investigate the incidence of heterotopic ossification (HO) in the Bryan cervical arthroplasty group and to identify associations between preoperative factors and the development of HO. METHODS: We performed a retrospective review of clinical and radiological data on patients who underwent single-level cervical arthroplasty with Bryan prosthesis between January 2005 and September 2007. Patients were postoperatively followed-up at 1, 3, 6, 12 months and every year thereafter. The clinical assessment was conducted using Odom's criteria. The presence of HO was evaluated on the basis of X-ray at each time-point according to the McAfee classification. In this study, we focused on survivorship of Bryan prosthesis for single-level arthroplasty. The occurrence of ROM-affecting HO was defined as a functional failure and was used as an endpoint for determining survivorship. RESULTS: Through the analysis of 19 cases of Bryan disc arthroplasty for cervical radiculopathy and/or myelopathy, we revealed that ROM-affecting HO occurs in as many as 36.8% of cases and found that 37% of patients had ROM-affecting HO within 24 months following surgery. The overall survival time to the occurrence of ROM-affecting HO was 36.4 ± 4.4 months. Survival time of the prosthesis in the patient group without preoperative uncovertebral hypertrophy was significantly longer than that in the patient group with preoperative uncovertebral hypertrophy (47.2 months vs 25.5 months, p = 0.02). Cox regression proportional hazard analysis illustrated that preoperative uncovertebral hypertrophy was determined as a significant risk factor for the occurrence of ROM-affecting HO (hazard ratio = 12.30; 95% confidential interval = 1.10-137.03; p = 0.04). CONCLUSION: These findings suggest that the condition of the uncovertebral joint must be evaluated in preoperative planning for Bryan cervical arthroplasty.

Intraosseous schwannoma with ancient change on the lumbar spine.

A 65-year-old male was admitted for progressive lower back pain. The preoperative revealed an osteolytic expansile mass with a sclerotic margin involving the right lamina and pedicle of L2. The histopathology revealed an ancient schwannoma. We report a rare case of an intraosseous ancient schwannoma involving lumbar vertebra along with its imaging findings and surgical aspects.

Significance of interfacet distance, facet joint orientation, and lumbar lordosis in spondylolysis.

The aim of this study is to reveal the association between lumbar spondylolysis and several radiologic parameters, which had been suggested to be significant. The authors examine interfacet distance (IFD), facet joint orientation (FJO), and lumbar segmental lordosis (LSL) all together on the basis of lumbar computed tomography (CT) scan of 35 patients with L5 spondylolysis and 36 unaffected control groups. Thirty-five Korean military recruits, aged 19-23 (mean 20.9 years), were diagnosed as L5 spondylolysis by lumber CT scans. As a control group, 36 male Korean military recruits, aged 18-25 (mean 21.3 years), were reconfirmed as not affected by lumbar spondylolysis by CT scan when they visited our hospital complaining of back pain. This study compares IFD, FJO, and LSL for each lumbar segment between the spondylolytic and unaffected groups. We also propose the use of normal mean data of IFD, FJO, and LSL of lumbar vertebrae from 36 Korean young military recruits because each measurement has power as an absolute value, like data from an osteologic collection in other studies. Comparison of IFD between spondylolytic and unaffected individuals reveals significant differences at the L3, L4, and L5 level (P = 0.0384, P = 0.0219, and P < 0.0001, respectively). In the group of spondylolysis, the increase of IFD from L4 to S1 was less pronounced (P < 0.0001) and the LSL at L5-S1 was more lordotic (P = 0.0203). Interfacet distance and lumbar lordosis were significantly different between patients with L5 spondylolysis and individuals without pars defect on L5. In the spondylolysis group, and the increase of IFD from L4 to S1 was less pronounced and the LSL at L5-S1 was more lordotic.