Percutaneous Epidural Neuroplasty for Symptomatic Lumbar Juxtafacet Cysts.

Background and Objectives: The term "Juxtafacet cyst" refers to both synovial cysts and ganglion pseudocysts associated with the lumbar facet joint. As conservative treatment for the juxtafacet cyst has a minimal effect, complete excision through surgery is considered the first choice of treatment. In this study, we retrospectively reviewed the clinical outcomes of percutaneous epidural neuroplasty for symptomatic lumbar juxtafacet cysts. Materials and Methods: We conducted a retrospective review of 34 patients with symptomatic juxtafacet cysts who visited a single institute from January 2010 to September 2023. Patients who received conservative treatment for at least 6 weeks but experienced no or insufficient effects were eligible for this study. After neuroplasty, a medical history check and neurological examination were performed during follow-up at 2 weeks, 1 month, 2 months, 3 months, 6 months, and once a year thereafter. Results: The pain improved for all patients to a VAS score of 3 or less immediately after neuroplasty; however, four of those patients (11%) had pain that worsened eventually to the same level as before the procedure and required surgery. The results showed that, regardless of cyst size, in cases with severe stenosis of the spinal canal, the outcome of neuroplasty was poor and often eventually required surgery. The cyst size was not associated with the procedure results. In addition, if the cyst was present at the L4-L5 level, or if diabetes mellitus was present, the likelihood of future surgery was significant (p-value = 0.003). Conclusions: Percutaneous neuroplasty showed a better success rate than other non-surgical treatments. In addition, severe spinal stenosis (Schizas grade C or higher), L4-L5 level, or diabetes mellitus produced a high possibility of surgery due to recurrence.

Manipulating the Cathodic Modification Effect on Corrosion Resistance of High Corrosion-Resistant Titanium Alloy.

Further improving the corrosion resistance of the ASTM Grade 13 (Gr13) titanium alloy was achieved by manipulating the cathodic modification effect. The cathodic modification of Gr13 was mainly related to the Ti2Ni precipitate, where minor Ru was contained and controlled the precipitate in terms of size and distribution, which could manipulate the cathodic modification effect. Parameters such as temperature and cooling rate during the recrystallization process were designed to control precipitation behavior, where the temperature at 850 °C was selected to allow the full dissolution of the Ti2Ni precipitate. The cooling rate, as high as 160.9 °C/min, was still enough for precipitation to occur during the cooling stage, leading to the formation of the Ti2Ni precipitate along with a grain boundary. The cooling rate of water quenching was too fast to cause the diffusion process, resulting in a large amount of the ß-Ti phase without the precipitate, which was pre-formed while heated at 850 °C. Aging at 600 °C caused the re-precipitation of Ti2Ni, and, at that moment, the precipitate was refined and separated, as a good aspect of the catalyst for HER. Therefore, the aged sample after water quenching showed the lowest onset potential for HER with the highest corrosion potential, indicating that its passivation ability was improved by the strengthened cathodic modification effect. This improvement was confirmed by the OCP results, where passivation survival was observed for the aged sample due to the highest cathodic modification effect. Therefore, the aged sample, which had refined and separate precipitates, showed the lowest corrosion rate.

Patterns of initial disease recurrence after resection of biliary tract cancer.

OBJECTIVES: This study aimed to provide further insights into the indications for adjuvant therapeutic strategies via analysis of the sites of initial recurrence after resection of gallbladder cancer (GBC) and intrahepatic (IHC) and extrahepatic cholangiocarcinoma (EHC). METHODS: Patients with biliary tract cancer who underwent potentially curative resection were identified from the database. Sites of initial disease recurrence were categorized as locoregional or distant. RESULTS: Between March 2001 and April 2009, 231 patients underwent curative resection. Initial GBC and IHC recurrence involving a distant site occurred in 70.8 and 86.8% patients, respectively, compared to 56.9% patients with EHC (p = 0.002). The median time to disease recurrence (TTR) was shorter among the GBC and IHC groups compared with that in EHC patients (6.3 and 6.7 vs. 13.1 months, respectively; p = 0.003). Moreover, median times to distant recurrence in GBC and IHC groups were shorter than that in EHC (5.8 and 6.5 vs. 14.1 months, respectively; p = 0.002). CONCLUSIONS: After resection, recurrent GBC and IHC are more likely to involve a distant site and are associated with significantly shorter TTR than recurrent EHC. These findings suggest that an adjuvant therapeutic strategy targeting distant disease is likely to have a significant impact on the overall management of GBC and IHC.

Stereotactic radiosurgery for central neurocytoma: a quantitative systematic review.

Central neurocytoma was originally described as a rare benign neuronal tumor. However, progression and local recurrences after surgery are well recognized. Stereotactic radiosurgery is another option for treatment of CN. In order to evaluate the efficacy of SRS, we performed a quantitative systematic review of the available data on SRS for CN. To identify eligible studies, systematic searches for all CNs treated with SRS were conducted in major scientific publication databases. English studies published prior to May 2011 were reviewed and summarized with reference to the inclusion and exclusion criteria. Tumor local control was analyzed. Heterogeneity and publication bias were assessed, and the summary control rate and 95%confidence interval (CI) were calculated from the raw data.Of 35 eligible studies, five with a total of 64 CNs were included in this quantitative analysis. Four studies reported a mean or median follow-up time of[60 months. The test of heterogeneity was non-significant among the included studies. Publication bias was observed as indicated by an asymmetric funnel plot. There was non-significance in Begg's test and Egger's test. The estimated cumulative rate of neuro-imaging tumor control was 91.1% (95%CI = 80.2­96.3%) at a mean follow-up of 59.3 months(range 6­140 months). The P-value was\0.0001 under a random-effect model. Sensitivity analysis showed a similar summary control rates (89.5­93.7%). Based on the summary local control rate of SRS for CN found in this quantitative analysis, we suggest that single session SRS is an effective and safe alternative therapy for recurrent or residual CN. However, the results of our analysis are limited by the predominance of case series studies due to scarcity of published research. Further randomized trials of CN patients via multicenter consortia should be considered for supplementing the weak points in our quantitative analysis.

Effect of the initial structure on the electrical property of crystalline silicon films deposited on glass by hot-wire chemical vapor deposition.

Crystalline silicon films on an inexpensive glass substrate are currently prepared by depositing an amorphous silicon film and then crystallizing it by excimer laser annealing, rapid thermal annealing, or metal-induced crystallization because crystalline silicon films cannot be directly deposited on glass at a low temperature. It was recently shown that by adding HCI gas in the hot-wire chemical vapor deposition (HWCVD) process, the crystalline silicon film can be directly deposited on a glass substrate without additional annealing. The electrical properties of silicon films prepared using a gas mixture of SiH4 and HCl in the HWCVD process could be further improved by controlling the initial structure, which was achieved by adjusting the delay time in deposition. The size of the silicon particles in the initial structure increased with increasing delay time, which increased the mobility and decreased the resistivity of the deposited films. The 0 and 5 min delay times produced the silicon particle sizes of approximately 10 and approximately 28 nm, respectively, in the initial microstructure, which produced the final films, after deposition for 300 sec, of resistivities of 0.32 and 0.13 Omega-cm, mobilities of 1.06 and 1.48 cm2 V(-1) S(-1), and relative densities of 0.87 and 0.92, respectively.

The management of vertebral artery injury in anterior cervical spine operation: a systematic review of published cases.

PURPOSE: Anterior cervical spine operations (ACSO) are generally considered to be safe and effective, but the vertebral artery (VA) is at risk during the procedure. Because the consequences of VA injury can be catastrophic, properly managing a VA injury is very important. However, due to the rarity of these injuries, there is no agreed upon treatment strategy. METHODS: Studies were identified for inclusion in the review via sensitive searches of electronic databases through 31 December 2011. All cases included in the review were qualitatively analyzed to explore the relationship between type of VA injury management and neurological complications. RESULTS: Seventeen articles describing 39 cases of VA injury during ACSO were included in this study. Seven patients (17.9 %) had neurological complications followed by VA insufficiency. Two patients (5.1 %) had root damage due to ligation. One case (2.6 %) resulted in intraoperative death due to fatal bleeding. Delayed vascular complications were identified in nine (45.0 %) of the 20 patients that underwent only tamponade or hemostatic agent during the operation. Four patients underwent intraoperative endovascular treatment, and three of these patients had a cerebral infarction. All three patients who underwent clipping also had neurological complications. The five patients treated by direct repair did not have any complications. CONCLUSION: Our review suggests the management of VA injury should be considered in order listed: (1) performing tamponade with a hemostatic agent, (2) direct repair, (3) postoperative endovascular procedures to prevent delayed complications. If tamponade fails to achieve proper hemostasis, additional procedures as endovascular embolization, clipping and ligation should be considered but carry the risk of neurological complications. Because of the limitations of this review, further studies are recommended with larger sample sizes.

A Nationwide Study on the Impact of COVID-19 Pandemic on Volume of Spine Surgery in South Korea.

OBJECTIVE: In March 2020, World Health Organization declared a global pandemic caused by a novel coronavirus (SARS-CoV-2). The disease caused by this virus is called COVID-19. Due to its high contagiousness, many changes have occurred in overall areas of our daily life including hospital use by patients. The aim of this study was to investigate the impact of COVID-19 on volume of spine surgery in South Korea using the National Health Insurance database and compare it with the volume of a homologous period before the pandemic. METHODS: Data of related to spine surgery from January 2019 to April 2021 were obtained from the National Health Insurance and Health Insurance Review and Assessment Service database. Primary outcomes were total number of patients, rate of patients per 100000 population, and total number of procedures. The number of patients by hospital size was also analyzed. RESULTS: COVID-19 outbreaks occurred in South Korea in March, August, and December of 2020. Compared to the previous year, the total number of patients who underwent spinal surgery showed a decrease for 2-3 months after the first and second outbreaks. However, it showed an increasing trend after the third outbreak. The same pattern was observed in terms of the ratio of the number of patients per 100000 population. Between 2019 and 2021, the mean number of spine surgeries per month tended to increase. Mean annual medical expenses increased over the years (p=0.001). When the number of spine surgeries was analyzed by hospital size, proportion of tertiary general hospital in 2021 increased compared to those in 2019 and 2020 (vs. 2019, p=0.012; vs. 2020, p=0.016). The proportion of general hospital was significantly decreased in 2020 compared to that in 2019 (p=0.037). CONCLUSION: After the COVID-19 outbreak, patients tended to postpone spinal surgery temporarily. The number of spinal surgeries decreased for 2-3 months after the first and second outbreaks. However, as the ability to respond to the COVID-19 pandemic at the hospital and society-wide level gradually increased, the number of spine surgeries did not decrease after the third outbreak in December 2020. In addition, the annual number of spine surgeries continued to increase. However, it should be noted that patients tend to be increasingly concentrated in tertiary hospitals for spinal surgery.

Interchangeability for Biologics is a Legal Distinction in the USA, Not a Clinical One.

Biologics are increasingly vital medicines that significantly reduce morbidity as well as mortality, yet access continues to be an issue even in apparently wealthy countries, such as the USA. While patient access is expected to improve with the introduction of biosimilars, misperceptions in a significant part based on terminology continue to make a sustained contribution by biosimilars difficult. Patients are and will continue to suffer needlessly if biosimilars continue to be impugned. Consequently, it is increasingly urgent that semantics are clarified, and in particular, the implication that interchangeable biologics are better biosimilars dismissed. This paper distinguishes between the real differences between biologics that matter clinically to patients and discusses the actual meaning of a US Food and Drug Administration designation of interchangeability for a biosimilar product. This will help highlight where there is need for further Food and Drug Administration education and which stakeholders likely need that education the most.

N-type crystalline silicon films free of amorphous silicon deposited on glass by HCl addition using hot wire chemical vapour deposition.

Since n-type crystalline silicon films have the electric property much better than those of hydrogenated amorphous and microcrystalline silicon films, they can enhance the performance of advanced electronic devices such as solar cells and thin film transistors (TFTs). Since the formation of amorphous silicon is unavoidable in the low temperature deposition of microcrystalline silicon on a glass substrate at temperatures less than 550 degrees C in the plasma-enhanced chemical vapour deposition and hot wire chemical vapour deposition (HWCVD), crystalline silicon films have not been deposited directly on a glass substrate but fabricated by the post treatment of amorphous silicon films. In this work, by adding the HCl gas, amorphous silicon-free n-type crystalline silicon films could be deposited directly on a glass substrate by HWCVD. The resistivity of the n-type crystalline silicon film for the flow rate ratio of [HCl]/[SiH4] = 7.5 and [PH3]/[SiH4] = 0.042 was 5.31 x 10(-4) ohms cm, which is comparable to the resistivity 1.23 x 10(-3) ohms cm of films prepared by thermal annealing of amorphous silicon films. The absence of amorphous silicon in the film could be confirmed by high resolution transmission electron microscopy.

Effect of Iron Content on Corrosion Properties of Pure Titanium as Grain Refiner.

Microstructures and corrosion properties of pure titanium were characterized when iron was used as a grain refiner. The added Fe element acted as a strong grain refiner for pure titanium by forming ß Ti phase at grain boundaries, and 0.15 wt% Fe was revealed to be a sufficient amount to make the grain size of pure titanium below 20 µm, which was the requirement for the desired titanium cathode. However, corrosion resistance was decreased with the Fe amount added. From the open circuit potential (OCP) results, it was obvious that the TiO2 stability against the reducing acid environment was deteriorated with the Fe amount, which seemed to be the main reason for the decreased corrosion resistance. Electrochemical impedance spectroscopy (EIS) results showed that both the decrease in the compact oxide film's resistance (Rb) and the appearance of the outer porous film occurred as a result of the dissolution of the TiO2 layer, whose phenomena became more apparent as more Fe was added.

Central Sarcopenia, Frailty and Comorbidity as Predictor of Surgical Outcome in Elderly Patients with Degenerative Spine Disease.

OBJECTIVE: People are living longer and the elderly population continues to increase. The incidence of degenerative spinal diseases (DSDs) in the elderly population is quite high. Therefore, we are facing more cases of DSD and offering more surgical solutions in geriatric patients. Understanding the significance and association of frailty and central sarcopenia as risk factors for spinal surgery in elderly patients will be helpful in improving surgical outcomes. We conducted a retrospective cohort analysis of prospectively collected data to assess the impact of preoperative central sarcopenia, frailty, and comorbidity on surgical outcome in elderly patients with DSD. METHODS: We conducted a retrospective analysis of patients who underwent elective spinal surgery performed from January 1, 2019 to September 30, 2020 at our hospital. We included patients aged 65 and over who underwent surgery on the thoracic or lumbar spine and were diagnosed as DSD. Central sarcopenia was measured by the 50th percentile of psoas : L4 vertebral index (PLVI) using the cross-sectional area of the psoas muscle. We used the Korean version of the fatigue, resistance, ambulation, illnesses, and loss of weight (K-FRAIL) scale to measure frailty. Comorbidity was confirmed and scored using the Charlson Comorbidity Index (CCI). As a tool for measuring surgical outcome, we used the Clavien-Dindo (CD) classification for postoperative complications and the length of stay (LOS). RESULTS: This study included 85 patients (35 males and 50 females). The mean age was 74.05±6.47 years. Using the K-FRAIL scale, four patients were scored as robust, 44 patients were pre-frail and 37 patients were frail. The mean PLVI was 0.61±0.19. According to the CD classification, 50 patients were classified as grade 1, 19 as grade 2, and four as grade 4. The mean LOS was 12.35±8.17 days. Multivariate stepwise regression analysis showed that postoperative complication was significantly associated with surgical invasiveness and K-FRAIL scale. LOS was significantly associated with surgical invasiveness and CCI. K-FRAIL scale showed a significant correlation with CCI and PLVI. CONCLUSION: The present study demonstrates that frailty, comorbidity, and surgical invasiveness are important risk factors for postoperative complications and LOS in elderly patients with DSD. Preoperative recognition of these factors may be useful for perioperative optimization, risk stratification, and patient counseling.

The Influence of Comorbidities on Reoperations Following Primary Surgery of Lumbar Degenerative Diseases : A Nationwide Population-Based Retrospective Cohort Study from 2009-2016.

OBJECTIVE: Spinal degeneration is a progressive disease, worsening over time. Lumbar degenerative disease (LDD) is a major spinal disease in elderly patients. Surgical treatment is considered for medically intractable patients with LDD and reoperation after primary surgery is not uncommon. The surgical outcome is occasionally unpredictable because of comorbidities. In the present study, the relationship between comorbidities and the incidence of reoperation for LDD over time was determined. METHODS: The claims data of the health insurance national database were used to identify a cohort of patients who underwent spinal surgery for LDD in 2009. The patients were followed up until 2016. Medical comorbidity was assessed according to the Charlson comorbidity index (CCI). Cox proportional hazard regression modeling was used to identify significant differences in sex, surgery, age, causative disease, and comorbidity. RESULTS: The study cohort included 78241 patients; 10328 patients (13.2%) underwent reoperation during the observation period. The reoperation rate was statistically higher (p<0.01) in males, patients 55-74 years and 65-74 years of age, and patients with decompression or discectomy. Significant association was found between increasing reoperation rate and CCI score (p<0.01). Based on multivariate analysis of comorbidities, the significantly higher reoperation rates were observed in patients with peripheral vascular disease, pulmonary lung disease, peptic ulcer, diabetes, and diabetes complications (p<0.01). CONCLUSION: The study results indicate the reoperation rate for LDD is associated with patient comorbidities. The comorbidities identified in this study could be helpful in future LDD studies.

Current Training Status of Neurosurgical Residents in South Korea: A Nationwide Multicenter Survey.

BACKGROUND: In South Korea, special legislation was introduced in December 2016 to limit residents' training time to a maximum of 80 hours per week. The aim of this study was to survey the current training system and environment of neurosurgical residents and to find ways to improve the quality of neurosurgical training. METHODS: The questionnaire survey included 373 neurosurgical residents at 66 training hospitals nationwide, who were members of the Korean Neurosurgical Society. The survey method included a questionnaire link through a text message and was carried out anonymously. The survey was conducted for 7 days and targeted a total of 106 residents (28.4%). RESULTS: Most respondents selected "excessive training time" as a reason for dissatisfaction with the training environment (n = 61, 57.5%), followed by "limited number of opportunities for surgery" (n = 50, 47.2%), and "little experience for research" (n = 42, 39.6%). Respondents still believe that they have to work excessively longer, even after 80 hours of training per week. CONCLUSIONS: The major reason that neurosurgical residents are dissatisfied with the current training system and environment is the excessive time spent on it. These survey results are expected to be used as the basis for improvement of the residents' training system and work environment in South Korea.

Disappearance of Arachnoid Cyst after Burrhole Trephination: Case Series.

We report 3 cases of arachnoid cysts (ACs) that completely disappeared after burr hole drainage, without cyst fenestration into the subarachnoid space or cystoperitoneal shunt. The first patient was a 21-year-old female with an AC of the right cerebral convexity, found incidentally. After endoscopic AC fenestration was performed, the patient complained of persistent headache. Two-month postoperative brain imaging revealed reaccumulated AC and associated multi-stage subdural hematoma. Burr hole drainage was performed to resolve the chronic subdural hematoma (CSDH). Three months later, brain computed tomography showed that the CSDH and the AC had disappeared. The second patient was an 11-year-old male who had a history of trauma 1 month prior to presentation at the clinic. Brain magnetic resonance imaging revealed an AC in the left sylvian fissure with CSDH. We performed burr hole drainage to treat the CSDH first. Subsequently, the AC as well as the CSDH disappeared. The third case was an AC of the right parietal convexity, found incidentally. Only burr hole drainage was performed, following which, the AC disappeared. This case series shows that an AC can disappear naturally after rupture into the subdural space by trauma or the burr hole procedure.

Spark Plasma Sintering Behavior of Nb-Mo-Si Alloy Powders Fabricated by Hydrogenation-Dehydrogenation Method.

In this study, the sintering behaviors of Nb-6Mo-20Si-3Cr (at percentage) in situ composite powders were studied. The Nb alloy powder was fabricated by a hydrogenation-dehydrogenation method, and both the alloy ingot and powders consisted of two phases: An Nb metal phase and the α-Nb5Si3 phase. Consolidation of the alloy powders was performed at 1500, 1600, and 1700 °C using spark plasma sintering, and the microstructures and phases formed at various sintering temperatures were analyzed. Micropores were observed in the compact sintered at 1500 °C due to the lack of complete densification at that temperature. The densification was completed at 1600 °C and the microstructure was slightly coarsened at 1700 °C compared to the microstructure of the compact sintered at 1600 °C. The microstructures prepared by the powder metallurgy method were finer than the microstructure of the ingot prepared by the casting method. The phase formation behavior varied according to the sintering temperature. Specifically, the α-Nb5Si3 phase, which is a stable structure of the Nb5Si3 phase at a low temperature, was transformed to the ß-Nb5Si3 phase (which is stable at a high temperature) with an increasing sintering temperature.

Morphological study of sinus flow in the confluence of sinuses.

The confluence of sinuses (CS; torcular herophili) is represented by the junction of the superior sagittal (SSS), straight (SS), occipital (OS), and two transverse sinuses (TS). The objective of this study was to interpret sinus flow around the CS by morphological investigation of the sinuses. This study is based on visual examination of dural venous sinuses in the region of the CS in 31 adult cadavers. In the inflow zone, we examined the direction of SSS and SS flow. In the communication zone, we examined the extent to which outflow sinuses communicate with other sinuses. In the outflow zone, we used the diameters of outflow sinuses to determine anatomical dominance. The SSS entered the CS via the right TS in 16 cases (51.6%) and via the center of the CS in 14 cases (45.2%). The SS entered via the center of the CS in 18 cases (58.1%) and via the left TS in 11 cases (35.5%). Outflow sinuses communicated freely in 26 cases (83.8%) and communicated partially in five cases (16.2%). Partial communication was the result of a septate CS. In terms of outflow, the right TS was dominant in 11 cases (35.5%), and in 18 cases (58.1%), outflow was symmetrical. The direction of SSS inflow was different from that of SS inflow, and partial communication was observed in five cases (16.1%). Therefore, the presence of a septum may be considered an anatomical factor, with implications in diagnosis or in the sacrifice of the outflow sinus of the CS.

Calcium pyrophosphate dihydrate deposition disease in the temporomandibular joint: diagnosis and treatment.

BACKGROUND: Calcium pyrophosphate dihydrate deposition disease (CPDD) is a rare disease in the temporomandibular joint (TMJ) space. It forms a calcified crystal mass and induces a limitation of joint movement. CASE PRESENTATION: The calcified mass in our case was occupied in the left TMJ area and extended to the infratemporal and middle cranial fossa. For a complete excision of this mass, we performed a vertical ramus osteotomy and resected the mass around the mandibular condyle. The calcified mass in the infratemporal fossa was carefully excised, and the segmented mandible was anatomically repositioned. Scanning electronic microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) microanalysis was performed to evaluate the calcified mass. The result of SEM/EDS showed that the crystal mass was completely composed of calcium pyrophosphate dihydrate. This result strongly suggested that the calcified mass was CPDD in the TMJ area. CONCLUSIONS: CPDD in the TMJ is a rare disease and is difficult to differentially diagnose from other neoplasms. A histological examination and quantitative microanalysis are required to confirm the diagnosis. In our patient, CPDD in the TMJ was successfully removed via the extracorporeal approach. SEM/EDS microanalysis was used for the differential diagnosis.

Surgical approaches to paraspinal nerve sheath tumors.

OBJECT: The goal of this study was to analyze the results of surgical treatment of paraspinal nerve sheath tumors (NSTs) and review the surgical approaches to paraspinal NSTs. METHODS: A retrospective review of the cases of paraspinal NSTs treated surgically by two senior authors during the period between 1970 and 2006 was undertaken. Surgical approaches that allow minimal disruption of normal anatomy and are aimed at complete resection of paraspinal lesions and preservation of spinal stability are reviewed according to the spinal level. RESULTS: Eighty-eight paraspinal NSTs were treated surgically during the period: 56 schwannomas, seven solitary neurofibromas, 21 neurofibromas associated with neurofibromatosis Type 1 (NF1), and four malignant peripheral NSTs. Schwannomas tended to occur in the cervical and thoracic areas. Neurofibromas were usually associated with NF1 and tended to occur in the cervical area. Pain (79 patients, 90%) and paresthesia (81 patients, 92%) were the predominant clinical presenting symptoms; others included weakness (28 patients) and myelopathy (12 patients). Total resection of the tumor was achieved in 50 patients (89.3%) with schwannomas and 22 patients (78.6%) with neurofibromas. There was a large reduction of pain in 70 (88.6%) of 79 patients who had preoperative pain, and weakness improved in 18 (64.3%) of 28. Postoperative transient weakness occurred in 12 (42.9% ) of these patients, but in 85% of this group, the symptom improved over a 12-month period. Myelopathy was reduced in eight (66.7%) of 12 patients. The average follow-up period was 18 months. CONCLUSIONS: Paraspinal NSTs present unique surgical challenges given their anatomical relationships to the spine, spinal cord, nerve roots, and major vasculature. The surgical technique should take into account the location of the lesion and its relationship to paraspinal anatomy, the extent of resection, sparing of normal anatomy, and spinal instability.

Long-Term Outcome of Posterior Cervical Inclinatory Foraminotomy.

OBJECTIVE: A modified surgical technique of posterior cervical foramintomy called posterior cervical inclinatory foraminotomy (PCIF) was introduced in previous preliminary article. PCIF allows better preservation of facet joint and capsule than conventional techniques. The authors conducted a study to investigate long-term outcomes of PCIF. METHODS: We retrospectively reviewed demographic, radiologic, and clinical data from the patients who underwent PCIFs at our institution. Criteria included a minimum of 48 month follow-up and PCIFs for patients with radiculopathy from foraminal stenosis (C2-T1; single or multilevel) with persistent or recurrent root symptoms despite conservative treatment for more than 3 months. Patients who had undergone previous cervical operation were excluded. The visual analogue scale (VAS) score was used for clinical follow-up, and radiologic follow-up was performed to compare the changes of cervical sagittal alignment, focal angle and disc-space height of treated segment. RESULTS: The PCIFs were performed between April 2007 and March 2011 on 46 patients (32 males and 14 females) with a total of 73 levels affected. The average duration of follow-up was 74.4 months. Improvements in radiculopathic pain were seen in 39 patients (84.7%), and VAS score decreased from 6.82±1.9 to 2.19±1.9. Posterior neck pain also improved in 25 patients (71.4%) among 35 patients, and VAS score decreased from 4.97±2.0 to 2.71±1.9. The mean disc-space heights of treated segment were 5.41±1.03 mm preoperatively and decreased to 5.17±1.12 mm postoperatively. No statistically significant changes in cervical sagittal alignment, focal angle were seen during the follow-up period (Cox proportional hazards analysis and Student t-test, p>0.05). CONCLUSION: The PCIF is highly effective in treating patients with cervical spondylotic radiculopathy, leading to long-lasting relief in pain. Long-term radiologic follow-up showed no significant spinal angular imbalance.

Predictors of Reoperation after Microdecompression in Lumbar Spinal Stenosis.

OBJECTIVE: The risk factors of reoperation after microdecompression (MD) for lumbar spinal stenosis (LSS) are unclear. In this study, we presented the outcomes of MD for degenerative LSS and investigated the risk factors associated with reoperation. METHODS: A retrospective review was conducted using the clinical records and radiographs of patients with LSS who underwent MD. For clinical evaluation, we used the Japanese Orthopedic Association (JOA) scoring system for low back pain, body mass index, and Charlson comorbidity index. For radiological evaluation, disc height, facet angle, and sagittal rotation angle were measured in operated segments. Also the Modic change and Pfirrmann grade for degeneration in the endplate and disc were scored. RESULTS: Forty-three patients aged 69±9 years at index surgery were followed for 48±25 months. The average preoperative JOA score was 6.9±1.6 points. The score improved to 9.1±2.1 points at the latest follow-up (p<0.001). Seven patients (16.3%) underwent reoperation. Clinical and radiological factors except operation level and Pfirrmann grade showed a p-value >0.1. Patients with Pfirrmann grade IV and lower lumbar segment had a 29.1% rate of reoperation (p=0.001), whereas patients without these factors had a 0% rate of reoperation. CONCLUSION: Moderate disk degeneration (Pfirrmann IV) in lower lumbar segments is a risk factor of disk herniation or foraminal stenosis requiring reoperation after MD in LSS.