Predictive Value of Modified Frailty Index, Sarcopenia, Prognostic Nutritional Index, and Geriatric Nutritional Risk Index for Postoperative Complications in Oblique Lumbar Interbody Fusion over 60 Years.

OBJECTIVE: Elderly patients undergoing spinal surgery are at an increased risk of morbidity and mortality. Evaluating frailty and preoperative status is crucial for predicting postoperative outcomes. This study aimed to assess the predictive value of the modified Frailty Index (mFI), sarcopenia, Prognostic Nutritional Index (PNI) and Geriatric Nutritional Risk Index (GNRI) in determining postoperative complications in patients undergoing oblique lumbar interbody fusion (OLIF) over 60 years. METHODS: Preoperative risk factors were assessed using 11 variables, including mFI, PNI, GNRI. Complication rates were compared among nonfrail (mFI = 0; n = 50), prefrail (mFI = 0.09-0.18; n = 144), and frail (mFI ≥0.27; n = 80) patients. Demographic and perioperative variables were compared between the complication and noncomplication groups. The incidence of complications was the primary outcome measure. RESULTS: Complications occurred in 36 of 274 patients (13.1%). The frail group exhibited a significantly higher incidence of pneumonia than the nonfrail and prefrail groups. The complication group displayed significant differences in several variables, including age, fusion level, albumin level, lymphocyte count, platelet count, creatinine level, and estimated blood loss. Moreover, mFI, PNI, and GNRI differed significantly between the complication and noncomplication groups. CONCLUSION: MFI, PNI, and GNRI can be useful for predicting postoperative morbidity and mortality in patients undergoing OLIF. These comprehensive assessment methods enable the identification of high-risk patients and the formulation of tailored strategies to enhance postoperative outcomes. Integrating mFI, PNI, and GNRI into the preoperative evaluation process can help healthcare providers proactively manage high-risk patients, thus improving the overall quality of care for elderly individuals undergoing OLIF.

Spinal Neurenteric Cyst of the Ventral Cervicothoracic Junction With Klippel-Feil Syndrome as a Symptom of Progressive Myelopathy: A Case Report.

Neurenteric cysts are rare and account for only 0.7%-1.3% of all spinal tumors. Spinal neurenteric cysts are associated with spina bifida, split-cord malformations, and Klippel-Feil syndrome, a rare congenital disorder characterized by fusion of two or more cervical vertebrae. Klippel-Feil syndrome is rarely accompanied by neurenteric cysts. In this case report, we describe a cervicothoracic junction neurenteric cyst associated with Klippel-Feil syndrome in a 30-year-old man who presented with a 2-month history of neck pain with radiation of pain into both arms and a 1-month history of weakness in the left arm. Magnetic resonance imaging (MRI) of the spine revealed an expansive intradural extramedullary cystic lesion anterior to the spinal cord at the cervicothoracic junction. The neurenteric cyst was removed using an anterior approach, accompanied by C5-C6 corpectomy. The patient's condition improved postoperatively, and he was discharged after postoperative MRI. Spinal neurenteric cysts should be considered in the differential diagnosis in cases of vertebral developmental abnormalities concurrent with intraspinal cysts.

Bone Substitute Options for Spine Fusion in Patients With Spine Trauma-Part II: The Role of rhBMP.

In Part II, we focus on an important aspect of spine fusion in patients with spine trauma: the pivotal role of recombinant human bone morphogenetic protein-2 (rhBMP-2). Despite the influx of diverse techniques facilitated by technological advancements in spinal surgery, spinal fusion surgery remains widely used globally. The persistent challenge of spinal pseudarthrosis has driven extensive efforts to achieve clinically favorable fusion outcomes, with particular emphasis on the evolution of bone graft substitutes. Part II of this review aims to build upon the foundation laid out in Part I by providing a comprehensive summary of commonly utilized bone graft substitutes for spinal fusion in patients with spinal trauma. Additionally, it will delve into the latest advancements and insights regarding the application of rhBMP-2, offering an updated perspective on its role in enhancing the success of spinal fusion procedures.

Effect of Furosemide on Prevertebral Soft Tissue Swelling after Anterior Cervical Fusion: A Comparative Study with Dexamethasone.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to investigate the effect of furosemide on prevertebral soft tissue swelling (PSTS) after anterior cervical fusion (ACF) and compare it with the effect of dexamethasone. OVERVIEW OF LITERATURE: Postoperative PSTS is a common complication of ACF. Dexamethasone has been used for its treatment; however, its efficacy remains controversial. Furosemide may reduce PSTS if it is soft tissue edema; however, no studies have demonstrated the effect of furosemide on PSTS after ACF. METHODS: The symptomatic PSTS group received intravenous (IV) administration of dexamethasone or furosemide. The asymptomatic PSTS group did not receive any medication. Patients were divided into the control (no medication, n=31), Dexa (IV dexamethasone, n=25), and Furo (IV furosemide, n=28) groups. PSTS was checked daily with simple radiographs and medication-induced reductions in PSTS from its peak or after medication. RESULTS: The peak time (postoperative days) of PSTS in the control (2.27±0.47, p<0.05) and Dexa (1.91±0.54, p<0.01) groups were significantly later than that in the Furo group (1.38±0.74). PSTS was significantly lower in the Furo group than in the Dexa group from postoperative days 4 to 7 (p<0.05). PSTS reduction after the peak was significantly greater in the Furo group than in the control (p<0.01) and Dexa (p<0.01) groups. After starting the medication therapy, the Furo group showed a significantly greater reduction in PSTS than the Dexa group (p<0.01). No difference was found in symptom improvement among the three groups. CONCLUSIONS: If furosemide is used to reduce PSTS after ACF, it can effectively reduce symptoms.

Clinical impact of craniectomy on shunt-dependent hydrocephalus after intracerebral hemorrhage: A propensity score-matched analysis.

PURPOSE: A consensus on decompressive craniectomy for intracerebral hemorrhage (ICH) has not yet been established. We aimed to investigate the development of shunt-dependent hydrocephalus based on the method of ICH surgery, with a focus on craniectomy. METHODS: We retrospectively enrolled 458 patients with supratentorial ICH who underwent surgical hematoma evacuation between April 2005 and December 2021 at two independent stroke centers. Multivariate analyses were performed to characterize risk factors for postoperative shunt-dependent hydrocephalus. Propensity score matching (1:2) was undertaken to compensate for group-wise imbalances based on probable factors that were suspected to affect the development of hydrocephalus, and the clinical impact of craniectomy on shunt-dependent hydrocephalus was evaluated by the matched analysis. RESULTS: Overall, 43 of the 458 participants (9.4%) underwent shunt procedures as part of the management of hydrocephalus after ICH. Multivariate analysis revealed that intraventricular hemorrhage (IVH) and craniectomy were associated with shunt-dependent hydrocephalus after surgery for ICH. After propensity score matching, there were no statistically significant intergroup differences in participant age, sex, hypertension status, diabetes mellitus status, lesion location, ICH volume, IVH occurrence, or IVH severity. The craniectomy group had a significantly higher incidence of shunt-dependent hydrocephalus than the non-craniectomy group (28.9% vs. 4.3%, p < 0.001; OR 9.1, 95% CI 3.7-22.7), craniotomy group (23.2% vs. 4.3%, p < 0.001; OR 6.6, 95% CI 2.5-17.1), and catheterization group (20.0% vs. 4.0%, p = 0.012; OR 6.0, 95% CI 1.7-21.3). CONCLUSION: Decompressive craniectomy seems to increase shunt-dependent hydrocephalus among patients undergoing surgical ICH evacuation. The decision to perform a craniectomy for patients with ICH should be carefully individualized while considering the risk of hydrocephalus.

Effect of Mixture of Recombinant Human Bone Morphogenic Protein-2 and demineralized Bone Matrix in Lateral Lumbar Interbody Fusion.

Objective: This study aims to determine the optimal dose of recombinant-human Bone Morphogenic Protein-2 (rhBMP-2) for successful bone fusion in minimally invasive Lateral Lumbar Interbody Fusion (MIS LLIF). Previous studies show that rh-BMP is an effective alternative to autologous iliac crest bone graft, but the optimal dose remains uncertain. The study analyzes the fusion rates associated with different rh-BMP doses to provide a recommendation for the optimal dose in MIS LLIF. Methods: 93 patients underwent MIS LLIF using demineralized bone matrix (DBM) or a mixture of rhBMP-2 and DBM as fusion material. The group was divided into the following three groups according to the rhBMP-2 usage. Group A (only DBM was used, n: 27). Group B (1mg of rhBMP-2 per 5cc of DBM paste, n: 41). Group C (2mg of rhBMP-2 per 5cc of DBM paste, n: 25). Demographic data, clinical outcomes, postoperative complication and fusion were assessed. Results: At 12 months post-surgery, the overall fusion rate was 92.3% according to Bridwell fusion grading system. Group B and C, who received rhBMP-2, had significantly higher fusion rates than group A, who received only DBM. However, there was no significant increase in fusion rate when the rhBMP-2 dosage was increased from group B to group C. The group B and C showed significant improvement in back pain and ODI compared to the group A. The incidence of screw loosening was decreased in group B and C, but there was no significant difference in the occurrence of other complications. Conclusion: Usage of rhBMP-2 in LLIF surgery leads to early and increased final fusion rates, which can result in faster pain relief and return to daily activities for patients. The benefits of using rhBMP-2 were not significantly different between the groups that received 1mg/5cc and 2mg/5cc of rhBMP-2. Therefore, it is recommended to use 1mg of rhBMP-2 with 5cc of DBM, taking both economic and clinical aspects into consideration.

Kummell's Disease is Becoming Increasingly Important in an Aging Society: A Review.

Kummell's disease (KD) is referred to as delayed posttraumatic vertebral collapse, avascular necrosis of vertebrae, or ischemic vertebral collapse. KD is no longer rare in an aging society. It is mainly caused by minor trauma, and nonunion occurs secondary to avascular necrosis at the vertebral body fracture site, which can lead to vertebral kyphosis or intravertebral instability. Clinical symptoms of KD range from no symptoms to severe paralysis due to nerve injury. KD is considered a complication of osteoporotic vertebral compression fractures, and conservative treatment, including osteoporosis treatment, is important. Timely interventions such as vertebral augmentation or surgery, with active regular follow-up are necessary before the onset of neurological deficits due to osteonecrotic collapse in patients with suspected KD. In this study, we summarize the pathogenesis, diagnosis, and treatment of KD, which is showing increasing prevalence in an aging society. We have presented a literature review and discussed clinical guidelines and therapeutic strategies to reduce the morbidity and mortality associated with KD.

Bone Substitute Options for Spine Fusion in Patients With Spine Trauma-Part I: Fusion Biology, Autografts, Allografts, Demineralized Bone Matrix, and Ceramics.

Spinal trauma accounts for a large portion of injuries to the spine area, particularly as societies are entering an era of aging populations. Consequently, spine fractures accompanied by osteoporosis are becoming more prevalent. Achieving successful fusion surgery in patients with spine fractures associated with osteoporosis is even more challenging. Pseudarthrosis in the spine does not yield clinically favorable results; however, considerable effort has been made to achieve successful fusion, and the advancement of bone graft substitutes has been particularly crucial in this regard. Autograft bone is considered the best fusion material but is limited in use due to the quantity that can be harvested during surgery and associated complications. Accordingly, various bone graft substitutes are currently being used, although no specific guidelines are available and this mainly depends on the surgeon's choice. Therefore, the purpose of this review, across part I/II, is to summarize bone graft substitutes commonly used in spine surgery for spine fusion in patients with spine trauma and to update the latest knowledge on the role of recombinant human bone morphogenetic protein-2.

Occlusion of Both Vertebral Arteries With Development of Collateral Circulation From the Deep Cervical Artery After Cervical Spine Trauma.

Careful evaluation of vertebral artery injuries is important after cervical translation injuries or transverse foramen fractures. Treatment of trauma can be complicated in cases of concomitant vertebral artery injuries. A 76-year-old woman was admitted to our hospital with left hemiparesis (Motor grade 3) after a motorcycle accident. Cervical spine magnetic resonance imaging (MRI) and computed tomography (CT) revealed a C3 burst fracture and a left C3 lateral mass and lamina fracture. CT angiography revealed fracture fragments that predisposed the vertebral artery to injury throughout its course in the area. CT angiography confirmed that both vertebral arteries were occluded at the C3 fracture site. Subsequent brain MRI revealed acute infarction in the right occipital area. Although both vertebral arteries were occluded, the infarction site did not correspond to the territory supplied by these vessels; therefore, we performed transfemoral cerebral angiography, which revealed collateralization of the bilateral vertebral arteries by the deep cervical artery.. The deep cervical arteries are located between the posterior muscles; therefore, a fixation operation performed using the posterior approach may have affected the collateral circulation and led to exacerbation of the infarction site. Therefore, surgery was performed using an anterior approach and it was possible to minimize the risk of cerebral infarction through preservation of collateral circulation.

Importance of Surgical Order for Minimizing Vascular Injury During the L5-S1 Approach in Multilevel Oblique Lateral Interbody Fusion Surgery.

Objective: In oblique lateral interbody fusion (OLIF) surgery at the L5-S1 level (OLIF51), anatomical complexity and the possibility of vascular injury during retraction of the common iliac vein (CIV) make the surgery challenging. We radiologically evaluated patients who underwent OLIF surgery to determine approaches that can make OLIF51 surgery easier during multilevel OLIF. Methods: We retrospectively analyzed 275 consecutive patients who underwent OLIF surgery between September 2014 and December 2019. The distance between the left and right CIVs (dCIV) was measured using an axial image at the L5 lower endplate level, and the height of the iliocaval junction (hCIV) was measured from the L5 lower endplate to the iliocaval junction in the sagittal image. The sum of anterior disc height of each level (sADH) was calculated. Results: Eighty-two patients (33 males and 49 females) were enrolled. The number of three- (L2-3-4-5), two- (L3-4-5), and one-level (L4-5) fusions was 13, 21, and 48, respectively. Changes between the pre- and postoperative sADH, dCIV, and hCIV values were 17.1±4.7, 7.7±3.5, and 13.1±4.7 mm in three-level fusion; 10.6±4.1, 5.6±3.7, and 7.0±3.1 in two-level fusion; and 4.3±2.5, 3.3±2.7, and 3.0±2.0 mm in one-level fusion, respectively. As the number of surgical levels increased, the changes in sADH, dCIV, and hCIV significantly increased. Conclusions: The dCIV and hCIV values increased when the upper segment underwent surgery before OLIF51 during multilevel OLIF.

An Anatomical Clue for Minimizing Iliac Vein Injury During the Anterolateral Approach at L5-S1 Level: A Cadaveric Study.

OBJECTIVE: The injury to the common iliac vein (CIV) seems to be the most important concern during the anterior approach to the spine at L5-S1 level. We investigated the anatomy of the L5-S1 vertebral structures related to the CIV through a cadaveric study to find an anatomical clue for safe dissection of CIV. METHODS: Ten cadavers were prepared for this study. After removing the peritoneum and the presacral fascia, the section from the lower part of the L5 to the upper part of the S1 vertebral body was removed with the CIV attached. After decalcification, 2 sections in the vertical and horizontal directions were made for histological study. RESULTS: An adipose tissue layer was present between the intervertebral disc and CIV. The adipose tissue layer in 6 cadavers was thin, and in 3 of these cadavers, the CIV was attached to the vertebral body and the disc. In the other 4 cadavers, the CIV was clearly separated from the vertebral body and the disc by the intervening adipose tissue layer (IATL). Under the microscope, a thin layer surrounding the anterior longitudinal ligament, periosteum, and disc was observed, and we named this structure the 'perivertebral membrane'. The perivertebral membrane was attached to the CIV when there was no IATL, but a potential space was detected under the membrane. CONCLUSION: There was a thin membrane, perivertebral membrane, between the CIV and L5-S1 disc. In cases with CIV adhesion to the disc due to the absence of IATL, the CIV may be mobilized indirectly through the perivertebral membrane.

Impact of adolescent complex regional pain syndrome on the psychopathology of young men ahead of military service: a retrospective cohort analysis of Korean conscription data.

BACKGROUND: The relationship between physical and psychopathological features in complex regional pain syndrome (CRPS) has been a subject of constant interest, but no data are available in adolescents. Therefore, we aimed to identify the factors associated with psychopathology in adolescents with CRPS ahead of military service. METHODS: We retrospectively reviewed all conscription examinees who had completed a Military Personality Inventory (MPI) during a period between February 2013 and December 2016. A total of 63 persons with a history of CRPS (19-years of age for all) were enrolled. Basic demographic and pain-related data were analyzed to examine their association with MPI results. The mean FGR score as well as the 8 subdomain scores were compared between those with pain duration at < 15 months (n = 30) versus ≥15 months (n = 33). Binary MPI results (normal-abnormal) were also compared between the two groups. RESULTS: In multivariate analysis, abnormal MPI was associated with pain duration, with an odds ratio (OR) at 1.05 for every 1-month increase (95% confidence interval (CI) 1.02-1.08; P = 0.002). Subjects with pain duration at ≥15 months have lower faking good response score (P < 0.001 vs. those with pain duration at < 15 months), and higher abnormal MPI result rate, faking bad response, inconsistency, anxiety, depression, somatization, paranoid, personality disorder cluster A, and personality disorder cluster B scores (P < 0.05). Pain duration was significantly associated with the MPI variables. CONCLUSIONS: Pain duration is associated with psychopathology in adolescents with CRPS. Psychopathologic features increased as the disease duration increased. A comprehensive understanding of time-dependent psychopathological factors could support the planning of multimodal approaches for managing adolescent CRPS.

Relationship between Increased Intracranial Pressure and Mastoid Effusion.

OBJECTIVE: This study aimed to assess the relationship between increased intracranial pressure (ICP) and mastoid effusions (ME). METHODS: Between January 2015 and October 2018, patients who underwent intracranial surgery and had ICP monitoring catheters placed were enrolled. ICP was recorded hourly for at least 3 days. ME was determined by the emergence of opacification in mastoid air cells on follow-up brain imaging. C-reactive protein (CRP) levels, presence of endotracheal tube (ETT) and nasogastric tube (NGT), duration of intensive care unit (ICU) stay, duration of mechanical ventilator application, diagnosis, surgical modalities, and presence of sinusitis were recorded. Each factor's effect on the occurrence of ME was analyzed by binary logistic regression analyses. To analyze the independent effects of ICP as a predictor of ME a multivariable logistic regression analysis was performed. RESULTS: Total of 61 (53%) out of 115 patients had ME. Among the patients who had unilateral brain lesions, 94% of subject (43/50) revealed the ipsilateral development of ME. ME developed at a mean of 11.1±6.2 days. The variables including mean ICP, peak ICP, age, trauma, CRP, ICU stays, application of mechanical ventilators and presence of ETT and NGT showed statistically significant difference between ME groups and non-ME groups in univariate analysis. Sex and the occurrence of sinusitis did not differ between two groups. Adding the ICP variables significantly improved the prediction of ME in multivariable logistic regression analysis. CONCLUSION: While multiple factors affect ME, this study demonstrates that ICP and ME are probably related. Further studies are needed to determine the mechanistic relationship between ICP and middle ear pressure.

Preservation of Deep Cervical Extensor Muscle Volume: Comparison Between Conventional Open-Door and Muscle Preserving Laminoplasty Approaches in the Same Patients.

BACKGROUND: Surgical laminoplasty techniques have been developed to reduce cervical kyphosis and postoperative axial neck pain and preserve the posterior cervical extensor muscles. We compared a unilateral conventional open approach (OA) and a contralateral muscle preserving approach (MPA) for laminoplasty in the same patients to determine differences in the preservation of the posterior cervical muscles after the 2 approaches. METHODS: This study was a prospective observational study involving 44 patients who underwent laminoplasty with unilateral OA and contralateral MPA for cervical myelopathy from January 2005 to December 2013. The cross-sectional area (CSA) changes in the posterior cervical extensor muscles (multifidus, semispinalis cervicis, and semispinalis capitis muscles) were measured on computed tomography scan, both pre- and postoperatively. RESULTS: Using an OA, the multifidus and semispinalis cervicis muscle preservation was 58.2% and 67.0%, but using an MPA, muscle preservation was 97% and 90.8% (P < 0.001 and P = 0.042), respectively. However, the CSA of the semispinalis capitis muscle did not differ significantly between the 2 groups. In terms of the level, conservation of the multifidus muscle was significantly different according to the approach at all levels, and the conservation of the deep extensor muscles was significantly different at the C3-4 level. CONCLUSIONS: MPA was effective in preserving the volume of deep cervical extensor muscles and helping minimize postoperative musculoskeletal complications. In addition, muscle preservation was more effective at the C3-4 level.

Thrombolysis in Cerebral Infarction Grade 2C or 3 Represents a Better Outcome than 2B for Endovascular Thrombectomy in Acute Ischemic Stroke: A Network Meta-Analysis.

BACKGROUND: Although Thrombolysis in Cerebral Infarction (TICI) grade 2B or 3 is considered successful after endovascular thrombectomy (EVT) for acute ischemic stroke, TICI 2B was found to be associated with poorer outcomes than was 3. Furthermore, the newly proposed TICI 2C grade seems to be clinically equivalent to TICI 3 rather than to 2B. This network meta-analysis aimed to assess the differences in clinical outcomes between TICI grades and redefine successful reperfusion. METHODS: PubMed, Embase, and Cochrane Central Register were queried. A random-effect model with frequentist framework was applied to evaluate outcomes using odds ratios (ORs) and 95% confidence intervals (CIs). Using surface under the cumulative ranking curve (SUCRA), the hierarchy of TICI grades was indicated. RESULTS: Analysis of 12 studies, with 2084 patients, indicated that TICI 2C (OR, 2.28; 95% CI, 1.65-3.13) and 3 (OR, 2.40; 95% CI, 1.74-3.30) were significantly more associated with favorable 90-day clinical outcomes than were 2B; there was no significant difference between TICI 2C and 3 (OR, 1.05; 95% CI, 0.76-1.46). Based on the SUCRA, TICI 2C and 3 were considered as more effective reperfusion end points than was 2B (TICI 3, 80.8%; 2C, 69.2%; 2B, 0.0%) and showed significant association with lower rates of mortality and symptomatic intracranial hemorrhage. CONCLUSIONS: Patients with TICI 2C grade would be distinguished from those with 2B, because 2C is clinically equivalent to 3 and has a better outcome than 2B. Therefore, achieving 2C or 3 is likely to be closer to the successful aim of endovascular thrombectomy in acute ischemic stroke than achieving 2B.

Correction of marked sagittal deformity with circumferential minimally invasive surgery using oblique lateral interbody fusion in adult spinal deformity.

BACKGROUND: Spinal surgery performed entirely with minimally invasive surgery is referred to as circumferential MIS (cMIS). However, cMIS still has a limited sagittal correction capability for adult spinal deformity (ASD) with a marked sagittal deformity. We investigated the effectiveness of cMIS using oblique lateral interbody fusion (OLIF) and percutaneous posterior spine fixation in correcting marked sagittal deformity. METHODS: This study retrospectively evaluated 23 patients with ASD with marked sagittal deformity who underwent cMIS using OLIF without osteotomy and were followed-up for at least 24 months (whole group). The whole group was divided into the following two groups according to the type of interbody fusion at L5-S1: the OLIF51 group (n = 13) underwent OLIF at L1-L5 and L5-S1 and the TLIF51 group (n = 10) underwent OLIF at L1-L5 and transforaminal lumbar interbody fusion (TLIF) at L5-S1. RESULTS: Sagittal vertebral axis (SVA; 125.7 vs. 29.5 mm, p < 0.001), lumbar lordosis (LL; 18.2° vs. 51.7°, p < 0.001), and pelvic incidence-LL mismatch (PI-LL, 35.5° vs. 5.3°) significantly improved postoperatively in the whole group. The OLIF51 group showed significantly higher postoperative LL than the TLIF51 group (55.5° vs. 46.9°, p < 0.001). OLIF yielded a significantly greater disc angle at L5-S1 than did TLIF (18.4° vs. 6.9°, p < 0.001). Proximal junctional kyphosis occurred significantly earlier in the OLIF51 group than in the TLIF51 group (8.6 vs. 26.3 months, p < 0.001). CONCLUSION: Successful sagittal correction in ASD patients with marked sagittal deformity was achieved with cMIS using OLIF. OLIF at L5-S1 showed a synergistic effect in sagittal deformity correction by cMIS.

Usefulness of Oblique Lateral Interbody Fusion at L5-S1 Level Compared to Transforaminal Lumbar Interbody Fusion.

OBJECTIVE: The use of oblique lateral interbody fusion at the L5-S1 level (OLIF51) is increasing, but no study has directly compared OLIF51 and transforaminal lumbar interbody fusion (TLIF) at the L5-S1 level. We evaluated the usefulness of OLIF51 by comparing clinical and radiologic outcomes with those of TLIF at the same L5-S1 level. METHODS: We retrospectively reviewed and compared 74 patients who underwent OLIF51 (OLIF51 group) and 74 who underwent TLIF at the L5-S1 level (TLIF51 group). Clinical outcomes were assessed with the visual analogue scale for back pain and leg pain and the Oswestry Disability Index. Mean disc height (MDH), foraminal height (FH), disc angle (DA), fusion rate, and subsidence rate were measured for radiologic outcomes. RESULTS: The OLIF51 group used significantly higher, wider, and larger-angled cages than the TLIF51 group (p<0.001). The postoperative MDH and FH were significantly greater in the OLIF51 group than in the TLIF51 group (p<0.001). The postoperative DA was significantly larger in the OLIF51 group than in the TLIF51 group by more than 10º (p<0.001). The fusion rate was 81.1% and 87.8% at postoperative 6 months in the OLIF51 and TLIF51 groups, respectively, and the TLIF51 group showed a higher fusion rate (p<0.05). The subsidence rate was 16.2% and 25.3% in the OLIF51 and TLIF51 groups, respectively, and the OLIF51 group showed a lower subsidence rate (p<0.05). CONCLUSION: OLIF51 was more effective for the indirect decompression of foraminal stenosis, providing strong mechanical support with a larger cage, and making a greater lordotic angle with a high-angle cage than with TLIF.

A New Shielding Curtain for Protection of Intraoperative Radiation During Minimally Invasive Spine Surgery.

OBJECTIVE: Gradually increasing number of minimally invasive spine surgery (MISS), there is an increasing risk of radiation exposure to medical personnel during the surgery. We measured the radiation exposure of the operating room personnel during MISS, tried to find the riskiest person, and checked the effectiveness of a new lead-composite shielding curtain. METHODS: Radiation exposure of medical staffs (operator, first assistant, anesthesiologist, and scrub nurse) involved in MISS procedures of 35 patients without shielding curtain (nonshield group) and 35 patients with shielding curtain (shield group). The shielding curtain had 0.25-mm nominal lead equivalent and was mounted on 2 frame bars fixed on the operating table. RESULTS: In the nonshield group, radiation exposure was significantly higher in the order of operator > first assistant > scrub nurse > anesthesiologist (p < 0.001) during both anteroposterior (AP) and lateral views. In the shield group, the radiation exposure of the operator and the scrub nurse decreased significantly by 94.1% and 76.4% in AP view (p < 0.001), and by 96.3% and 73.9% in lateral view (p < 0.001), respectively. CONCLUSION: Since the radiation dose of the operator was highest in a C-arm-guided MISS, there is a high priority need to protect the operator from the radiation exposure. The shielding curtain could most effectively reduce the radiation exposure of the operator.

Locating the Instant Center of Rotation in the Subaxial Cervical Spine with Biplanar Fluoroscopy during In Vivo Dynamic Flexion-Extension.

BACKGROUND: Recently, biplanar fluoroscopy is used to evaluate the cervical kinematics, especially to locate the instant center of rotation (ICR) during in vivo motion. This study aims to ascertain the ICR at each cervical segment in the sagittal plane during dynamic motion and assess the differences from previous studies. METHODS: While three healthy subjects were performing full flexion-extension, two oblique views aligned horizontally and angled at approximately 55° were obtained by biplanar fluoroscopy. The minimum degree to detect significant movement in a helical axis model was set at 2°, and anterior-posterior and superior-inferior locations of each ICR were defined. To evaluate the possible distribution area and overlapping area of the ICR with disc space, we drew a circle by using the calculated distance between each coordination and the mean coordination of ICR as the radius. RESULTS: During flexion-extension motion, the mean superior-inferior location of the ICR became progressively more superior, except the C5-6 segment (p = 0.015), and the mean anterior-posterior location of the ICR became progressively more anterior without exception from C2-3 to C6-7 segments, but anterior-posterior ICR locations were not significantly different among segments. The overlapping area with the distribution circle of ICR was mainly located in the posterior half in the C3-4 segment, but the overlapping area was about 80% of the total disc space in C4-5 and C6-7 segments. The overlapping was more noticeable in the lower cervical segments after exclusion of the outlier data of the C5-6 segment in subject 1. CONCLUSIONS: The ICR in the cervical spine showed a trend of moving progressively more superiorly and anteriorly and the disc space overlapping the distribution circle of ICR increased along the lower motion segments except the C5-6 segment. These findings could provide a good basis for level-specific cervical arthroplasty designs.