Incidence, reasons, and risk factors for 30-day readmission after lumbar spine surgery for degenerative spinal disease.

This study investigated risk factors for 30-day readmission of discharged patients who had undergone lumbar spinal surgery. This retrospective, case-control study reviewed 3,933 patients discharged after elective spinal surgery for lumbar degenerative diseases from 2005 to 2012 at a university hospital. Of these patients, 102 were re-hospitalized within 30 days of discharge. Patient medical records were reviewed. The incidence of readmission within 30 days was 2.6%, and uncontrolled pain was the most common reason for readmission. In the univariate analysis, age, mental illness, the number of medical comorbidities, previous spinal surgery, fusion surgery, number of fusion levels, estimated blood loss, operation time, intensive care unit (ICU) admission, length of hospital stays, and total medical expenses were associated with a higher risk of readmission within 30 days. Multiple logistic regression analysis revealed that previous spinal surgery, operation time, ICU admission, length of hospital stays, and total medical expenses were independent risk factors for 30-day readmission. Independent risk factors for readmission were longer operation time, a previous spinal surgery, ICU admission, longer hospital stays, and higher medical expenses. Further studies controlling these risk factors could contribute to reducing readmission and thus improving the quality of care.

Diagnostic Value of Single-Photon Emission Computed Tomography/Computed Tomography Scans with Tc-99m HDP in Cervicogenic Headache.

A cervicogenic headache (CEH) is difficult to diagnose due to its varied pathology. We evaluated the usefulness of single-photon emission computed tomography/computed tomography (SPECT/CT) in diagnosing CEH and its interventional treatment. Retrospectively, 23 patients diagnosed with CEH between March 2016 to August 2018 were allocated to SPECT/CT (n = 11) and control (n = 12) groups. The SPECT/CT group was further stratified into SPECT/CT(+) and SPECT/CT(-) groups according to the presence of positive findings. Patients in the SPECT/CT group underwent an intra-articular injection at a radiologically verified lesion site, whereas those in the control group underwent third occipital nerve block. Clinical outcomes were evaluated with the visual analog scale (VAS), neck disability index (NDI), and global perceived effect (GPE) scale at baseline, and at one, three, and six months postoperatively. The SPECT/CT group showed less VAS, NDI, and GPE scores at six months postoperatively (2.91 ± 2.30 vs. 4.42 ± 1.62, p = 0.08; 38.00 ± 16.54 vs. 48.7 ± 12.40, p = 0.093; 2.00 ± 1.41 vs. 3.17 ± 1.11, p = 0.039). Successful responders at six months postoperatively were higher in the SPECT/CT(+) group than in the control group (75% vs. 0%). SPECT/CT can identify arthritic changes and accurately define therapeutic targets.

Contrast Dispersion on Epidurography May Be Associated with Clinical Outcomes After Percutaneous Epidural Neuroplasty Using an Inflatable Balloon Catheter.

BACKGROUND: Contrast dispersion pattern on epidurography may be associated with clinical improvement after epidural neuroplasty. However, insufficient evidence supports this theory. The current study aims to evaluate the relevance of contrast dispersion and clinical improvement after percutaneous epidural neuroplasty using an inflatable balloon catheter. METHODS: One hundred patients with lumbar spinal stenosis who underwent combined balloon decompression and epidural adhesiolysis between March 2015 to December 2015 participated in the present study. Participants were divided into two groups by contrast dispersion pattern on postprocedural epidurography: the complete contrast dispersion (CCD) and incomplete contrast dispersion (ICCD) groups. The numeric rating scale (NRS), Oswestry Disability Index (ODI), and global perceived effects (GPE) were each assessed before and one, three, six, nine, and 12 months after the intervention. RESULTS: After combined balloon decompression and adhesiolysis, significant pain reduction and functional improvement were maintained up to 12 months in patients with lumbar spinal stenosis. NRS and GPE in the CCD group were significantly lower than in the ICCD group from six to 12 months after the intervention. The ODI in the CCD group was also significantly lower compared with that in the ICCD group from one to 12 months after the intervention. CONCLUSIONS: Combined balloon decompression and adhesiolysis with the inflatable balloon catheter can provide noteworthy pain reduction and improvement of physical function for a long-term period in patients with lumbar spinal stenosis. Because CCD showed better clinical improvement compared with ICCD, a contrast dispersion pattern may be associated with an improved clinical outcome.

Efficacy of a Novel Annular Closure Device after Lumbar Discectomy in Korean Patients : A 24-Month Follow-Up of a Randomized Controlled Trial.

OBJECTIVE: Lumbar discectomy is an effective treatment for lumbar disc herniation (LDH); however, up to 2-18% of patients with LDH have experienced recurrent disc herniation. The purpose of this study was to evaluate the efficacy of a novel annular closure device (ACD) for preventing LDH recurrence and re-operation compared with that of conventional lumbar discectomy (CLD). METHODS: In this prospective randomized controlled trial, we compared CLD with discectomy utilizing the Barricaid® (Intrinsic Therapeutics, Inc., Woburn, MA, USA) ACD. Primary radiologic outcomes included disc height, percentage of preoperative disc height maintained, and re-herniation rates. Additional clinical outcomes included visual analog scale (VAS) scores for back and leg pain, Oswestry Disability Index (ODI) scores, and 12-item short-form health survey (SF-12) quality of life scores. Outcomes were measured at preoperation and at 1 week, 1, 3, 6, 12, and 24 months postoperation. RESULTS: Sixty patients (30 CLD, 30 ACD) were enrolled in this study. At 24-month follow-up, the disc height in the ACD group was significantly greater than that in the CLD group (11.4±1.5 vs. 10.2±1.2 mm, p=0.006). Re-herniation occurred in one patient in the ACD group versus six patients in the CLD group (χ2=4.04, p=0.044). Back and leg VAS scores, ODI scores, and SF-12 scores improved significantly in both groups compared with preoperative scores in the first 7 days following surgery and remained at significantly improved levels at a 24-month follow-up. However, no statistical difference was found between the two groups. CONCLUSION: Lumbar discectomy with the Barricaid® (Intrinsic Therapeutics, Inc.) ACD is more effective at maintaining disc height and preventing re-herniation compared with conventional discectomy. Our results suggest that adoption of ACD in lumbar discectomy can help improve the treatment outcome.

Factors Associated with Successful Response to Balloon Decompressive Adhesiolysis Neuroplasty in Patients with Chronic Lumbar Foraminal Stenosis.

Epidural neuroplasty, often called percutaneous epidural adhesiolysis, is often performed in refractory patients with chronic lumbar radiculopathy or neurogenic claudication. Recent studies have showed that decompressive adhesiolysis with an inflatable balloon catheter (balloon neuroplasty) is efficient in patients who experience refractory pain from epidural steroid injection or even epidural neuroplasty with a balloon-less catheter. However, exact indications or predictive factors for epidural balloon neuroplasty have not been fully evaluated. Therefore, to assess associated factors that could affect a favorable outcome, we analyzed a prospectively collected multicenter cohort of patients with chronic refractory lumbar foraminal stenosis after balloon neuroplasty. At the 6-month point in follow-up, 92 (44.4%) patients among 207 subjects were classified as successful responders according to a robust combination of outcome measures. Multivariate logistic regression analysis also showed that mild grade lumbar foraminal stenosis may be an independent factor associated with a successful response 6 months after balloon neuroplasty (odds ratio = 2.829; 95% confidence interval = 1.351-5.923; p = 0.006). However, we found that there were 29.4% and 24.6% successful responders with moderate and severe foraminal stenosis, respectively. Attempting balloon neuroplasty in refractory lumbar foraminal stenosis, especially mild grade, may be worthwhile. .

Clinical Effectiveness of Percutaneous Epidural Neuroplasty According to the Type of Single-Level Lumbar Disc Herniation : A 12-Month Follow-Up Study.

OBJECTIVE: To determine whether the outcomes of percutaneous epidural neuroplasty (PEN) are influenced by the type of lumbar disc herniation (LDH) and evaluate the effectiveness of PEN in patients with single-level LDH. METHODS: This study included 430 consecutive patients with single-level LDH who underwent PEN. Before treatment, the LDH type was categorized as bulging, protrusion, extrusion, and sequestration, while Pfirrmann grades were assigned according to imaging findings. Visual analog scale (VAS) scores for back and leg pain and success rates (Odom's criteria) were assessed at 1, 3, 6, and 12 months after treatment. RESULTS: The mean preoperative VAS scores for back and leg pain were 6.90 and 4.23, respectively; these decreased after PEN as follows : 2.25 and 1.45, respectively, at 1 month; 2.61 and 1.68, respectively, at 3 months; 2.28 and 1.48, respectively, at 6 months; and 2.88 and 1.48, respectively, at 12 months (p<0.001). The decrease in VAS scores for leg pain was significantly greater in the extrusion and sequestration groups than in the other two groups (p<0.05); there were no other significant differences among groups. More than 70% patients exhibited good or excellent 12-month outcomes according to Odom's criteria. Subsequent surgery was required for 59 patients (13.7%), with a significantly higher rate in the extrusion (25.0%) and sequestration (30.0%) groups than in the bulging (7.3%) and protrusion (13.8%) groups (p<0.05). Nevertheless, subsequent surgery was not required for >70% patients with extrusion or sequestration. Patients with Pfirrmann grades 1-3 (14.0-21.5%) showed a significantly higher rate of subsequent surgery than those with Pfirrmann grade 0 (4.9%; p<0.05). CONCLUSION: Our findings suggest that PEN is an effective treatment for back and leg pain caused by single-level LDH, with the outcomes remaining unaffected by the LDH type.

Relationship of Success Rate for Balloon Adhesiolysis with Clinical Outcomes in Chronic Intractable Lumbar Radicular Pain: A Multicenter Prospective Study.

Combined balloon decompression and epidural adhesiolysis has been reported to be effective in refractory lumbar spinal stenosis. Many cases of intractable stenosis have symptom-related multiple target sites for interventional treatment. In this situation it may not be possible to perform balloon adhesiolysis, or even only epidural adhesiolysis, for all target sites. Therefore, this multicenter prospective observational study aimed to evaluate the relationship of successful ballooning rate for multiple target sites with clinical outcome. Based on the ballooning success rate of multiple target sites, the patients were divided into three groups: below 50%, 50-85%, and above 85% ballooning. A greater ballooning success rate for multiple target sites provided a more decreased pain intensity and improved functional status in patients with chronic refractory lumbar spinal stenosis, and the improvement was maintained for 6 months. The estimated proportions of successful responders according to a multidimensional approach in the below 50%, 50-85%, and above 85% balloon success groups at 6 months after the procedure were 0.292, 0.468, and 0.507, respectively (p = 0.038). Our study suggests the more successful balloon adhesiolysis procedures for multiple target lesions are performed, the better clinical outcome can be expected at least 6 months after treatment.

Safety and Effectiveness of Transforaminal Epiduroscopic Laser Ablation in Single Level Disc Disease: A Case-Control Study.

BACKGROUND: The non-operative treatment of herniated intervertebral discs has long been a fundamental challenge. A novel technique of laser ablation to ablate the nucleus pulposus under a transforaminal epiduroscope (TELA system, Lutronics, Seoul, Republic of Korea) was recently developed. OBJECTIVE: The purpose of this study was to evaluate the safety and effectiveness of transforaminal epiduroscopic laser ablation (TELA) for selective ablation of the nucleus pulposus in single-level disc disease. STUDY DESIGN: Prospective case control studySETTING: Multicenter studyMETHODS: This study included a group of 56 patients who underwent transforaminal epiduroscopic laser ablation (TELA) and 56 patients who underwent selective transforaminal epidural block (STEB) for single-level disc disease. Visual analog scale (VAS), Oswestry Disability Index (ODI), and SF-12 were assessed at admission and at 1, 3, 6, and 12 months postoperatively. RESULTS: The mean VAS of back pain was lower for the TELA group than for the STEB group 12 months postoperative (P < 0.05). The mean ODI was lower in the TELA group than in the STEB group at 12 months postoperatively (P < 0.05). There were no major complications related to the TELA and STEB procedures. LIMITATIONS: The primary limitation is a small sample size. The control group was created from a database which was prospectively collected in a different time line. CONCLUSIONS: The TELA procedure is superior to the STEB procedure in terms of patients reporting less pain and better quality of life over a year. TELA may be a reasonable alternative to conventional interventions or open surgery in single-level disc disease. KEY WORDS: Laser-assisted spinal endoscopy, disc decompression, Nd:YAG laser, laser ablation, intervertebral disc disease, lumbar spine.

Biomechanical Analysis of Biodegradable Cervical Plates Developed for Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: In-vitro biomechanical investigation. PURPOSE: To evaluate the biomechanical effects of the degeneration of the biodegradable cervical plates developed for anterior cervical discectomy and fusion (ACDF) on fusion and adjacent levels. OVERVIEW OF LITERATURE: Biodegradable implants have been recently introduced for cervical spine surgery. However, their effectiveness and safety remains unclear. METHODS: A linear three-dimensional finite element (FE) model of the lower cervical spine, comprising the C4-C6 vertebrae was developed using computed tomography images of a 46-year-old woman. The model was validated by comparison with previous reports. Four models of ACDF were analyzed and compared: (1) a titanium plate and bone block (Tita), (2) strong biodegradable plate and bone block (PLA-4G) that represents the early state of the biodegradable plate with full strength, (3) weak biodegradable plate and bone block (PLA-1G) that represents the late state of the biodegradable plate with decreased strength, and (4) stand-alone bone block (Bloc). FE analysis was performed to investigate the relative motion and intervertebral disc stress at the surgical (C5-C6 segment) and adjacent (C4-C5 segment) levels. RESULTS: The Tita and PLA-4G models were superior to the other models in terms of higher segment stiffness, smaller relative motion, and lower bone stress at the surgical level. However, the maximal von Mises stress at the intervertebral disc at the adjacent level was significantly higher in the Tita and PLA-4G models than in the other models. The relative motion at the adjacent level was significantly lower in the PLA-1G and Bloc models than in the other models. CONCLUSIONS: The use of biodegradable plates will enhance spinal fusion in the initial stronger period and prevent adjacent segment degeneration in the later, weaker period.

Clinical Significance of Epidurography Contrast Patterns after Adhesiolysis during Lumbar Percutaneous Epidural Neuroplasty.

Background: The correlation between epidurography contrast patterns and the clinical outcomes of percutaneous epidural neuroplasty (PEN) remains unclear. Objective: To analyze the correlation between postadhesiolysis epidurography contrast patterns and the clinical outcomes of patients who undergo lumbar PEN. Design: This study is a retrospective analysis of 78 consecutive patients who underwent lumbar PEN between April 2012 and March 2013. Setting: The analysis was done in the university hospital center. Method: The clinical outcomes of all patients were assessed before and 1, 3, 6, and 12 months after undergoing lumbar PEN. Specifically, the intensity of back and leg pain, quality of life, and procedural outcomes were evaluated using a visual analog scale (VAS), the Oswestry Disability Index (ODI), and the 12-Item Short-Form Health Survey (SF-12). Results: The VAS scores for back and leg pain, ODI score, and SF-12 score exhibited a significant improvement during the follow-up period (P < 0.01 versus preprocedural scores). At most follow-up time points, patients exhibiting extraforaminal contrast distribution (n=22) on postadhesiolysis epidurograms exhibited a similar improvement in VAS scores and a significantly better improvement in ODI and SF-12 scores compared with patients exhibiting intracanal contrast distribution (n=56). Conclusion: Extraforaminal contrast distribution during lumbar PEN may be associated with better functional outcomes.

Clinical Course of Cervical Percutaneous Epidural Neuroplasty in Single-Level Cervical Disc Disease with 12-Month Follow-up.

BACKGROUND: Cervical disc disease is a common and occasionally disabling condition, occurring as a natural consequence of aging in the vast majority of the adult population. Percutaneous epidural neuroplasty (PEN) has been used to deliver highly concentrated drugs for chronic neck pain and to prevent scarring in cases refractory to conventional epidural blocks. However, the clinical course after PEN in cervical disc disease is not well-documented. OBJECTIVE: The purpose of this study was to evaluate the efficacy of cervical PEN for single-level cervical disc disease. STUDY DESIGN: A retrospective observational study. METHODS: A consecutive series of 100 patients who underwent cervical PEN for single-level disc disease (bulging or protrusion) were included in this study. Preoperatively, all patients underwent magnetic resonance imaging (MRI), and visual analog scale (VAS) scores as well as Odom's criteria were measured preoperatively and at post-operative follow-up visits (one, 3, 6, and 12 months). LIMITATIONS: The results of this study are limited by the lack of a control group that did not undergo treatment with PEN. RESULTS: Additional block therapy was performed in 58 patients (58.0%). Subsequent surgery was performed in 10 patients (10.0%, excluded from data of clinical follow-up). Mean neck pain and VAS arm pain scores for all follow-up patients decreased from 6.82 and 4.74 preoperatively to 2.18 and 1.87 at 12 months after PEN (P < 0.001). More than 80% and 40% of all patients with and without additional block therapy after cervical PEN, respectively, showed good and excellent outcomes according to Odom's Criteria during 12 months of follow-up. During this follow-up period, no severe complications related to the procedure were observed. CONCLUSION: Cervical PEN was shown to be a safe and effective treatment for neck and arm pain in single-level disc disease during 12 months of follow-up. Key words: Neck pain, cervical disc disease, pain management, percutaneous epidural neuroplasty, adhesiolysis, clinical course.

Inter- and Intra-Observer Variability of the Volume of Cervical Ossification of the Posterior Longitudinal Ligament Using Medical Image Processing Software.

OBJECTIVE: Computed tomography (CT)-based method of three dimensional (3D) analysis (MIMICS®, Materialise, Leuven, Belgium) is reported as very useful software for evaluation of OPLL, but its reliability and reproducibility are obscure. This study was conducted to evaluate the accuracy of MIMICS® system, and inter- and intra-observer reliability in the measurement of OPLL. METHODS: Three neurosurgeons independently analyzed the randomly selected 10 OPLL cases with medical image processing software (MIMICS®) which create 3D model with Digital Imaging and Communication in Medicine (DICOM) data from CT images after brief explanation was given to examiners before the image construction steps. To assess the reliability of inter- and intra-examiner intraclass correlation coefficient (ICC), 3 examiners measured 4 parameters (volume, length, width, and length) in 10 cases 2 times with 1-week interval. RESULTS: The inter-examiner ICCs among 3 examiners were 0.996 (95% confidence interval [CI], 0.987-0.999) for volume measurement, 0.973 (95% CI, 0.907-0.978) for thickness, 0.969 (95% CI, 0.895-0.993) for width, and 0.995 (95% CI, 0.983-0.999) for length. The intra-examiner ICCs were 0.994 (range, 0.991-0.996) for volume, 0.996 (range, 0.944-0.998) for length, 0.930 (range, 0.873-0.947) for width, and 0.987 (range, 0.985-0.995) for length. CONCLUSION: The medical image processing software (MIMICS®) provided detailed quantification OPLL volume with minimal error of inter- and intra-observer reliability in the measurement of OPLL.

Artificial Disk Replacement Combined With Fusion Versus 2-Level Fusion in Cervical 2-Level Disk Disease With a 5-Year Follow-up.

STUDY DESIGN: Prospective study. OBJECTIVE: The purpose of this study was to compare the long-term clinical and radiologic outcomes of hybrid surgery (HS) and 2-level anterior cervical discectomy and fusion (2-ACDF) in patients with 2-level cervical disk disease. SUMMARY OF BACKGROUND DATA: In a previous study with a 2-year follow-up, HS was shown to be superior to 2-ACDF, with a better Neck Disability Index (NDI) score, less postoperative neck pain, faster C2-C7 range of motion (ROM) recovery, and less adjacent ROM increase. MATERIALS AND METHODS: Between 2004 and 2006, 40 patients undergoing 2-level cervical disk surgery at our hospital were identified as 2-level degenerative disk disease. Forty patients were included in the previous study; 35 patients were followed up for 5 years. Patients completed the NDI and graded their pain intensity before surgery and at routine postoperative until 5 years. Dynamic cervical radiographs were obtained before surgery and at routine postoperative intervals and the angular ROM for C2-C7 and adjacent segments was measured. RESULTS: The HS group had better NDI recovery until 3 years after surgery (P<0.05). Postoperative neck pain was lower in the HS group at 1 and 3 years after surgery (P<0.05), but arm pain relief was not differently relieved. The HS group showed more angular ROM for C2-C7 at 2 and 3 years after surgery. The superior adjacent segment ROM showed hypermobility in the 2-ACDF group and hypomobility in the HS group at all follow-up periods without statistically significance, but the inferior adjacent segment ROM differed significantly (P<0.05). CONCLUSION: HS is superior to 2-ACDF; it leads to better NDI recovery, less postoperative neck pain, faster C2-C7 ROM recovery, and less adjacent ROM increase over a 2-year follow-up, but these benefits of HS become similar to those of 2-ACDF with 5 years of follow-up.

Sacral Reconstruction with a 3D-Printed Implant after Hemisacrectomy in a Patient with Sacral Osteosarcoma: 1-Year Follow-Up Result.

Pelvic reconstruction after sacral resection is challenging in terms of anatomical complexity, excessive loadbearing, and wide defects. Nevertheless, the technological development of 3D-printed implants enables us to overcome these difficulties. Here, we present a case of sacral osteosarcoma surgically treated with hemisacrectomy and sacral reconstruction using a 3D-printed implant. The implant was printed as a customized titanium prosthesis from a 3D real-sized reconstruction of a patient's CT images. It consisted mostly of a porous mesh and incorporated a dense strut. After 3-months of neoadjuvant chemotherapy, the patient underwent hemisacretomy with preservation of contralateral sacral nerves. The implant was anatomically installed on the defect and fixed with a screw-rod system up to the level of L3. Postoperative pain was significantly low and the patient recovered sufficiently to walk as early as 2 weeks postoperatively. The patient showed left-side foot drop only, without loss of sphincter function. In 1-year follow-up CT, excellent bony fusion was noticed. To our knowledge, this is the first report of a case of hemisacral reconstruction using a custom-made 3D-printed implant. We believe that this technique can be applied to spinal reconstructions after a partial or complete spondylectomy in a wide variety of spinal diseases.

An effect comparison of teriparatide and bisphosphonate on posterior lumbar interbody fusion in patients with osteoporosis: a prospective cohort study and preliminary data.

PURPOSE: Our purpose was to evaluate the efficacy of teriparatide for posterior lumbar interbody fusion (PLIF) in osteoporotic women. METHODS: Forty-seven osteoporotic patients underwent PLIF with pedicle screw fixation for degenerative lumbar stenosis and instability. Patients were divided into two groups. The teriparatide group (n = 23) was injected subcutaneously with teriparatide (20 µg daily) for 3-month cycles alternating with 3-month periods of oral sodium alendronate for 12 months. The bisphosphonate group (n = 24) was administered oral sodium alendronate (91.37 mg/week) for ≥1 year. Serial plain radiography, computed tomography, and bone mineral densitometry (BMD) evaluations were performed. Fusion rate, bony fusion duration, and T score changes were evaluated. Clinical data [pain scores, Prolo's functional scale, and Oswestry disability index (ODI)] were also serially evaluated. RESULTS: The teriparatide group showed earlier fusion than the bisphosphonate group. The average period of bone fusion was 6.0 ± 4.8 months in the teriparatide group but 10.4 ± 7.2 months in the bisphosphonate group. The bone fusion rate in the teriparatide group was higher than that in the bisphosphonate group at 6 months; however, there was no difference 12 and 24 months after surgery. Pain scores and ODI were not significantly different between groups. BMD scores in the teriparatide group were significantly improved compared with the bisphosphonate group 2 years after surgery. CONCLUSIONS: There was no significant improvement in overall fusion rate and clinical outcome in our patients after injection of teriparatide, but the teriparatide group showed faster bony union and highly improved BMD scores.

Finite Element Analysis of the Effect of Epidural Adhesions.

BACKGROUND: It is well documented that epidural adhesion is associated with spinal pain. However, the underlying mechanism of spinal pain generation by epidural adhesion has not yet been elucidated. OBJECTIVES: To elucidate the underlying mechanism of spinal pain generation by epidural adhesion using a two-dimensional (2D) non-linear finite element (FE) analysis. STUDY DESIGN: A finite element analysis. SETTING: A two-dimensional nonlinear FE model of the herniated lumbar disc on L4/5 with epidural adhesion. METHODS: A two-dimensional nonlinear FE model of the lumbar spine was developed, consisting of intervertebral discs, dura, spinal nerve, and lamina. The annulus fibrosus and nucleus pulpous were modeled as hyperelastic using the Mooney-Rivlin equation. The FE mesh was generated and analyzed using Abaqus (ABAQUS 6.13.; Hibbitt, Karlsson & Sorenson, Inc., Providence, RI, USA). Epidural adhesion was simulated as rough contact, in which no slip occurred once two surfaces were in contact, between the dura mater and posterior annulus fibrosus. RESULTS: The FE model of adhesion showed significant stress concentration in the spinal nerves, especially on the dorsal root ganglion (DRG). The stress concentration was caused by the lack of adaptive displacement between the dura mater and posterior annulus fibrosus. The peak von Mises stress was higher in the epidural adhesion model (Adhesion, 0.67 vs. Control, 0.46). In the control model, adaptive displacement was observed with decreased stress in the spinal nerve and DRG (with adhesion, 2.59 vs. without adhesion, 3.58, P < 0.00). LIMITATIONS: This study used a 2D non-linear FE model, which simplifies the 3D nature of the human intervertebral disc. In addition, this 2D non-linear FE model has not yet been validated. CONCLUSION: The current study clearly demonstrated that epidural adhesion causes significantly increased stress in the spinal nerves, especially at the DRG. We believe that the increased stress on the spinal nerve might elicit more pain under similar magnitudes of lumbar disc protrusion.

Paralytic Ileus and Prophylactic Gastrointestinal Motility Medication after Spinal Operation.

PURPOSE: To investigate the prevalence of paralytic ileus after spinal operation in the supine or prone operative position and to determine the efficacy of prophylactic gastrointestinal motility medications in preventing symptomatic paralytic ileus after a spinal operation. MATERIALS AND METHODS: All patients received spinal surgery in the supine or prone operative position. The study period was divided into two phases: first, to analyze the prevalence of radiographic and symptomatic paralytic ileus after a spinal operation, and second, to determine the therapeutic effects of prophylactic gastrointestinal motility medications (postoperative intravenous injection of scopolamine butylbromide and metoclopramide hydrochloride) on symptomatic paralytic ileus after a spinal operation. RESULTS: Basic demographic data were not different. In the first phase of this study, 27 patients (32.9%) with radiographic paralytic ileus and 11 patients (13.4%) with symptomatic paralytic ileus were observed. Radiographic paralytic ileus was more often noted in patients who underwent an operation in the prone position (p=0.044); whereas the occurrence of symptomatic paralytic ileus was not different between the supine and prone positioned patients (p=0.385). In the second phase, prophylactic medications were shown to be ineffective in preventing symptomatic paralytic ileus after spinal surgery [symptomatic paralytic ileus was observed in 11.1% (4/36) with prophylactic medication and 16.7% (5/30) with a placebo, p=0.513]. CONCLUSION: Spinal surgery in the prone position was shown to increase the likelihood of radiographic paralytic ileus occurrence, but not symptomatic paralytic ileus. Unfortunately, the prophylactic medications to prevent symptomatic paralytic ileus after spine surgery were shown to be ineffective.

Usefulness of 3-dimensional Measurement of Ossification of the Posterior Longitudinal Ligament (OPLL) in Patients With OPLL-induced Myelopathy.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate the usefulness of 3-dimensional (3D) measurement of ossification of the posterior longitudinal ligament (OPLL), and identify the reliability of a novel 3D method of measurement. SUMMARY OF BACKGROUND DATA: OPLL is not a 2-dimensional (2D) disease, but rather a 3D disease. Therefore, conventional measurement of parameters using radiography may not be suitable for evaluating OPLL. However, there is no study that investigated the correlation between 3D parameters of OPLL and clinical outcomes. METHODS: 50 patients (40 males and 10 females; mean age 57.2 yr) with symptomatic OPLL were enrolled. Neurological and clinical outcome scales were measured using the Japanese Orthopedic Association (JOA) score, visual analogue scale, short-form health survey (SF-36) and neck disability index. A 3D model was reconstructed with digital imaging and communications in medicine files from axial computed tomographic images using software (MIMICS; Materialise, Leuven, Belgium) to obtain the following parameters: 3D volume of OPLL, 3D volume of the spinal canal (confined to the vertebral level involving OPLL), spinal canal diameter, thickness of OPLL, and length of OPLL. All patients were divided into 2 different groups, the mild myelopathy group (JOA score ≥18, n = 11) and the severe myelopathy group (JOA score ≤17, n = 23). RESULTS: The 3D OPLL volume did not correlate with clinical outcomes (r =-0.275, P = 0.116). 3D OPLL ratio and OPLL thickness had a significant negative relationship with JOA score (r =-0.502, P < 0.005 and r =-0.437, P < 0.05, respectively). In particular, 3D OPLL ratio was an independent risk factor for increased severity of myelopathy (B =-29.71, P < 0.05). The mild myelopathy group showed lower 3D OPLL ratio than the severe myelopathy group (0.092 vs. 0.148, P < 0.05). CONCLUSION: 3D method of measurement is superior to the conventional method in terms of evaluating the clinical state of symptomatic patients with OPLL. Higher 3D OPLL ratio has an adverse effect on the spinal cord. LEVEL OF EVIDENCE: 3.

Efficacy and Safety of Sodium Hyaluronate with 1,4-Butanediol Diglycidyl Ether Compared to Sodium Carboxymethylcellulose in Preventing Adhesion Formation after Lumbar Discectomy.

OBJECTIVE: Epidural injection of hyaluronic acid may prevent adhesion formation after spine surgery, but the compounds used to stabilize hyaluronidase could interfere with its anti-adhesion effects. The present study was conducted as a clinical trial to evaluate the efficacy and safety of an experimental medical gel in preventing adhesion formation. METHODS: This study was designed as a multicenter, randomized, double-blind, and comparative controlled clinical trial with an observation period of 6 weeks. Subjects were randomly assigned into two groups: group A with sodium hyaluronate + 1,4-butanediol diglycidyl ether (BDDE) and group B with sodium hyaluronate + sodium carboxymethylcellulose (CMC). Visual analogue scale (VAS) of back and leg pain and the Oswestry disability index (ODI) and scar score ratings were assessed after surgery. RESULTS: Mean scar grade was 2.37±1.13 in group A and 2.75±0.97 in group B, a statistically significant difference (p=0.012). VAS of back and leg pain and ODI scores decreased significantly from baseline to 3 and 6 weeks postoperatively in both groups (p<0.001). However, VAS and ODI scores were not statistically different between groups A and B at baseline or at 3 and 6 weeks after operation (p>0.3). The number of adverse reactions related to the anti-adhesion gels was not statistically different (p=0.569), but subsequent analysis of nervous adverse reactions showed group B was superior with a statistically difference (p=0.027). CONCLUSION: Sodium hyaluronate with BDDE demonstrated similar anti-adhesion properties to sodium hyaluronate with CMC. But, care should be used to nervous adverse reactions by using sodium hyaluronate with BDDE.

Preliminary Experiences of the Combined Midline-Splitting French Door Laminoplasty with Polyether Ether Ketone (PEEK) Plate for Cervical Spondylosis and OPLL.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of cervical midline-splitting French-door laminoplasty with a polyether ether ketone (PEEK) plate. The authors retrospectively analyzed the results of patients with cervical laminoplasty miniplate (MAXPACER®) without bone grafts in multilevel cervical stenosis. METHODS: Fifteen patients (13 males and 2 females, mean age 50.0 years (range 35-72)) with multilevel cervical stenosis (ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy) underwent a combined surgery of midline-splitting French-door laminoplasty with or without mini plate. All 15 patients were followed for at least 12 months (mean follow-up 13.3 months) after surgery, and a retrospective review of the clinical, radiological and surgical data was conducted. RESULTS: The radiographic results showed a significant increase over the postoperative period in anterior-posterior diameter (9.4±2.2 cm to 16.2±1.1 cm), open angles in cervical lamina (46.5±16.0° to 77.2±13.1°), and sectional volume of cervical central canal (100.5±0.7 cm(2) to 146.5±4.9 cm(2)) (p<0.001). The sagittal alignment of the cervical spine was well preserved (31.7±10.0° to 31.2±7.6°, p=0.877) during the follow-up period. The clinical results were successful, and there were no significant intraoperative complications except for screw displacement in two cases. The mini plate constructs did not fail during the 12 month follow-up period, and the decompression was maintained. CONCLUSION: Despite the small cohort and short follow-up duration, the present study demonstrated that combined cervical expansive laminoplasty using the mini plate is an effective treatment for multilevel cervical stenosis.