Risk factors for spinal subdural hematoma after minimally invasive transforaminal lumbar Interbody Fusion (MI-TLIF): a multivariate analysis.

BACKGROUND: Spinal subdural hematoma (SSH) is a rare cause of compression of the neutral elements of the spinal cord. However, little is known about the presentation of acute SSH after lumbar spine surgery. The reason for this may be that symptomatic SSH occurs rarely and is not given enough attention by spine surgeons. Currently, the decision to perform MRI postoperatively is more dependent on surgeon preference; therefore, no high-quality studies have been published. Our team reports our experience in the diagnosis and management of SSH after lumbar decompression and fusion surgery. METHODS: We retrospectively studied 215 patients who underwent routine MRI following minimal invasive transforaminal lumbar interbody fusion (MI-TLIF) between 2020-01-01 and 2022-06-30. The patients were divided into SSH group (17 cases) and non-SSH group (198 cases) according to the occurrence of SSH. Univariate analysis and multivariate logistic regression analysis were performed to identify relevant risk factors that increase the risk of SSH postoperatively. RESULTS: None of the patients presented with serious neurologic symptoms, such as lower extremity paralysis or cauda equina syndrome that required emergency hematoma debridement. SSH was found in 17 (7.9%) patients and non-SSH in 198 (92.1%). Factors affecting SSH were presence of hypertension, presence of diabetes and postoperative anticoagulant therapy. The significantly independent risk factor of postoperative SSH were diabetes (P = 0.008, OR: 6.988) and postoperative anticoagulant therapy (P = 0.003, OR: 8.808). CONCLUSIONS: SSH after MI-TLIF is not a rare condition, with generally no requirement of emergency evacuation. Comprehensive anti-symptomatic treatment could achieve satisfactory results. Diabetes mellitus and postoperative anticoagulant therapy are independent risk factors for SSH. Spine surgeons should hold applicability of the use of anticoagulants after lumbar surgery.

Needle-Guided Suture Technique for Lumbar Annular Fiber Closure in Microendoscopic Discectomy: A Technical Note and Case Series.

BACKGROUND Annular fiber closure techniques have been proven effective in reducing short-term recurrence after discectomy. However, annular fiber closure devices are expensive and still fail at a low rate. We present a novel suture method, needle-guided annular closure suture (NGACS) that does not require a special device and can be performed for annular fiber closure following microendoscopic discectomy. MATERIAL AND METHODS Twenty-five patients who underwent treatment with NGACS were reviewed by analysis of the medical records. The clinical outcomes were assessed and compared preoperatively and immediately, 1, 6, and 12 months postoperatively. The parameters included the Visual Analog Scale (VAS)-back and VAS-leg scores and the Oswestry Disability Index (ODI). Midsagittal T2WI images were obtained to evaluate lumbar disc degeneration using the Pfirrmann grade. Additional adverse events were also recorded and tracked. RESULTS The VAS-back and VAS-leg scores and the ODI were significantly different at each follow-up time point (P<0.001), and improvements in pain and disability were maintained well during the follow-up period. Lumbar disc reherniation or other serious adverse events were not observed in this series. There was no significant difference between the initial and final Pfirrmann grades (Z=-1.414, P=0.157). The preoperative average disc height was 9.94±1.97 mm, and the disc height at 12 months after surgery was 9.14±1.88 mm. The average decrease in disc height was 8.11±3.36%. CONCLUSIONS This study demonstrates the feasibility and superior clinical outcomes of the NGACS technique. This method can be a good substitution when annular fiber closure devices are not available. Moreover, this technique can be easily popularized due to its low cost and few restrictions.

Bioactive mineralized small intestinal submucosa acellular matrix/PMMA bone cement for vertebral bone regeneration.

Polymethylmethacrylate (PMMA) bone cement extensively utilized for the treatment of osteoporotic vertebral compression fractures due to its exceptional handleability and mechanical properties. Nevertheless, the clinical application of PMMA bone cement is restricted by its poor bioactivity and excessively high modulus of elasticity. Herein, mineralized small intestinal submucosa (mSIS) was incorporated into PMMA to prepare a partially degradable bone cement (mSIS-PMMA) that provided suitable compressive strength and reduced elastic modulus compared to pure PMMA. The ability of mSIS-PMMA bone cement to promote the attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells was shown through cellular experiments carried out in vitro, and an animal osteoporosis model validated its potential to improve osseointegration. Considering these benefits, mSIS-PMMA bone cement shows promising potential as an injectable biomaterial for orthopedic procedures that require bone augmentation.

[Percutaneous transforaminal endoscopic foraminoplasty for simple lumbar spinal lateral exit-zone stenosis].

OBJECTIVE: To evaluate the clinical effects of percutaneous endoscopic foraminoplasty for simple lumbar spinal lateral exit zone stenosis. METHODS: A total of 36 patients with simple lumbar spinal lateral exit zone stenosis were admitted to our hospital from January 2013 to June 2018, and received selective nerve root canal radiography and radicular block. According to the symptoms and patients' personal wills, 22 cases underwent the one-stage percutaneous foraminal surgery(the one-stage operation group), and the other 14 patients were re-admitted to the hospital for operation(the delayed operation group) because of the recurrence of symptoms after discharge. The visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical effects before therapy, 1 day after the radicular block, and 1 day, 3 months and 6 months after the operation. RESULTS: VAS and ODI of all 36 cases were obviously improved (P<0.05) at various stages after the surgery and maintained well and showed a continuous downward trend. The VAS at 6 months after the operation was improved significantly compared with that at 1 day after the operation (P<0.05).When comparing the postoperative ODI between 1 day and 3 months after the surgery, 1 day and 6 months after the surgery, 3 months and 6 months after the surgery, the differences were statistically significant (P<0.05). The VAS and ODI of the one-stage operation group at 1 day after radicular block were better than those of delayed operation group. The VAS and ODI of delayed operation group before readmission were significantly higher than those at 1 day after radicular block. There were no significant differences in VAS and ODI at each stage after operation between two groups(P>0.05), but when compared with its own pretherapy andbefore readmission results, the difference was significant (P<0.05). There was no nerve injury in all cases. Only 2 cases were presented with the outlet root stimulation symptoms, and the symptoms relieved after short term conservative treatment. CONCLUSION: The clinical effects of radicular block may be unsustainable for patients with simple lumbar spinal lateral exit zone stenosis. Instead, percutaneous endoscopic foraminoplasty was simple, safe and effective.

Poly(methyl methacrylate) bone cement composited with mineralized collagen for osteoporotic vertebral compression fractures in extremely old patients.

To examine the clinical effects of a new bone cement composed of poly(methyl methacrylate) (PMMA) and mineralized collagen (MC) compared with pure PMMA bone cement in treating osteoporotic vertebral compression fractures (OVCFs) in patients aged over 80. In all, 32 cases using pure PMMA bone cement and 31 cases using MC-modified PMMA (MC-PMMA) bone cement for OVCFs between June 2014 and March 2016 were screened as PMMA group and MC-PMMA group, respectively, with an average age of over 80. The operation duration, intraoperative blood loss, hospital stay, oswestry disability index (ODI), visual analogue scale (VAS), anterior vertebral height (AVH), intermediate vertebral height (IVH) and posterior vertebral height (PVH) of injured vertebrae, vertebral computed tomography value, re-fracture rate of adjacent vertebrae, correction rate of spinal kyphotic angle and wedge-shaped vertebra angle and surgical complications were compared between the two groups. In the early post-operative period, the VAS, ODI, AVH and IVH in MC-PMMA group were comparable to those in the traditional PMMA group. Moreover, the MC-PMMA group showed better effects compared with the PMMA group 12 months after surgery. Thus, this new bone cement has superior clinic effects in the long term.

[Relationship between the prediction of the opening angle and the increased value of cross-sectional area in single open-door laminoplasty].

OBJECTIVE: To evolve the formula of relationship between opening angle of laminoplasty and the increased value of cross-sectional area, and to predict the opening angle according to the opening size of lanminoplasty. METHODS: From January 2013 to December 2015, 26 patients underwent single open-door laminoplasty in C3-C7. Among them, 10 patients with ossification of posterior longitudinal ligament, there were 6 males and 4 females, aged from 39 to 58 years old with an average of 49.2 years; and 16 patients with cervical spondylotic myelopathy, there were 10 males and 6 females, aged from 40 to 58 years old with an average of 50.2 years. Through the changes of spinal canal shape between preoperation and postoperation to set up the regular geometric model, and to deduce the formula of the relationship between the opening angle of laminoplasty and the increased value of cross-sectional area, and predict the formula of opening angle. According to the preoperative and postoperative CT scan, the needed parameters were measured, and were substituted in the above formula to get the change of cross-sectional area before and after operation, predicting the opening angle of laminoplasty. The differences between the change of cross-sectional area before and after operation, predictive the opening angle of laminoplasty and practical measured data were analyzed by statistical methods, thus to verify the feasibility of formula in practical application. RESULTS: All imaging data of 26 patients were obtained. There were significant differences in changes of cross-sectional areas in every patients (laminoplasty in C3 to C7) before and after operation in the same segment(P<0.01). The increasing extent in cross-sectional areas was gradually diminished following the opening angle increasing. There was no significant difference between the opening angle attained by formula and the data measured by software in the same segment(P>0.05). CONCLUSIONS: Increment of cross-sectional areas following C3-C7 laminoplasty can be accurately attained and the opening angle can also be predicted by a certain formula, which can help surgeons to attain the accurate opening angle and reduce the postoperative complications.

The positive correlation between upper adjacent vertebral fracture and the kyphosis angle of injured vertebral body after percutaneous kyphoplasty: An in vitro study.

OBJECTIVE: To investigate the correlation between the kyphosis angle of injured vertebral body and the risk of upper adjacent vertebral fracture after percutaneous kyphoplasty (PKP) using an osteoporotic vertebral compressed fracture model. MATERIALS AND METHODS: 24 functional spinal units (FSUs, T9 to L4) were selected from 6 elderly formalin preserved vertebral specimens to build the vertebral compressed fracture model. According to the kyphosis angle between the upper plate of upper vertebral body and the horizontal plane, group A (0°) and group B (20°) were defined, with each group comprised with 12 FSUs. The stiffness and fracture load were measured in both groups. RESULTS: After PKP, the stiffness was (571.513 ± 83.373)N/mm and the fracture load was (1751.659 ± 112.291)N in group A, with both significantly higher than those of group B (stiffness, (307.706 ± 46.723)N/mm; fracture load, (1128.011 ± 125.417)N). CONCLUSIONS: To reduce the risk of upper adjacent vertebral fracture, it is better to restore the height of injured vertebral body and decrease the angle of kyphosis to increase the capability of upper adjacent vertebral body against fracture.

[Long-term follow-up of Dynesys system in clinical application for the treatment of multiple lumbar degenerative disease].

OBJECTIVE: To explore the clinical effects of Dynesys system for the treatment of multiple segment lumbar degenerative disease. METHODS: A total of 28 patients with lumbar degenerative disc disease treated with Dynesys system from December 2008 to May 2011 were retrospectively reviewed. There were 16 males and 12 females, aged from 27 to 75 years old with an average of 49.1 years. Thirteen patients with multiple segmental lumbar intervertebral disc protrusion, including L3-L5 in 7 cases, L2-L4 in 1 case and L4-S1 in 5 cases. Fifteen patients with multiple segmental lumbar spinal stenosis, including L3-L5 in 10 cases, L4-L5 in 4 cases and L2-S1 in 1 case. The symptoms of lumbago and (or) intermittent claudication in all patients were treated with conservative treatments for more than 6 months and these methods did not work. Visual analogue scale (VAS) was used to analyze the lumbar and leg pain, imaging data were used to measure the intervertebral space height and intervertebral motion of fixed segment and upper adjacent segment, Oswestry Disability Index (ODI) was used to evaluate the clinical effect. RESULTS: All operations were successful and the patients were followed up from 38 to 65 months with an average 50.6 months. At final follow-up, ODI and VAS of the low back pain and leg pain were (25.10±6.52)%, (1.25±0.70) points and (1.29±0.89) points, respectively and were decreased compared with preoperative (P<0.05). Postoperative intervertebral space heights were increased and intervertebral motions were decreased in fixed segment compared with preoperative (P<0.05). There were no significant differences in intervertebral space heights and intervertebral motions of upper adjacent segment between preoperative and postoperative (P>0.05). CONCLUSION: Dynesys system may obtain long-term clinical curative effect in treating multiple lumbar degenerative disease. It can partially preserve the intervertebral motions of the fixed segments, have little effect on adjacent segments. The long-term clinical effect of Dynesys still need longer time follow-up observation.

[Clinical application of dynamic neutralization system (K-Rod) in treating multisegmental lumbar degenerative disease].

OBJECTIVE: To evaluate the clinical effects of dynamic neutralization system (K-Rod) in treating multisegmental lumbar degenerative disease. METHODS: From October 2011 to October 2013, 20 patients with multisegmental lumbar degenerative disease were treated with dynamic neutralization system (K-Rod). There were 8 males and 12 females with an average age of 45.4 years old (ranged from 31 to 65) and an average course of 3.8 years (ranged from 9 months to 6.25 years). All patients had the history of low back and legs pain. Among them, 10 cases were far lateral lumbar disc herniation, 7 cases were lumbar spinal stenosis, 3 cases were lumbar spondylolisthesis (degree I in 2 cases and degree II in 1 case). Every patient had only one responsible segment which causing the symptom would have to be rigidly fixed during operations, and the adjacent intervertebral disc of the responsible segments at least 1 segment has already obvious degenerated. All patients underwent the operation to relieve compressed nerves and reconstruct spinal stability with K-Rod system (the responsible segments were fixed with interbody fusion, and the adjacent segments were fixed with dynamic stabilization). Visual analogue scale (VAS), Japanese Orthopaedic Association Scores (JOA) and Oswestry Disability Index (ODI) were used to evaluate the clinical effects. Imaging data were used to analyze the range of motion (ROM), intervertebral disc height and intervertebral disc signal (according to modified Pfirrmann grading system) in degenerative adjacent segment. RESULTS: All patients were followed up for more than 1 year, and preoperative symptoms obviously relieved. There were significant differences in VAS, JOA, ODI between preoperative and postoperative (postoperative at 1 week and 1 year) (P<0.05). Radiological examination showed that all responsible segments had already fused, and no looseness, displacement and breakage of internal fixations were found. Postoperative at 1 year, the ROM of adjacent segments were decreased (P<0.05). There was no significant difference in intervertebral disc height between preoperative and postoperative at 1 year (P>0.05). According to modified Pfirrmann grading system to classification for the 25 disks of adjacent segment, 8 disks (32%) got improvement, 15 disks (60%) got no change and 2 disks (8%) got aggravation at 1 year after operation. CONCLUSION: Dynamic neutralization system (K-Rod) combined with interbody fusion could obtain short-term clinical effects in the treatment of multisegmental lumbar degenerative disease.

[Treatment of thoracolumbar deformity with transpedicular eggshell technique].

OBJECTIVE: To evaluate the clinical effects of transpedicular eggshell technique in treating thoracolumbar deformity. METHODS: From December 2008 to December 2011,36 patients with thoracolumbar deformity were treated with transpedicular eggshell technique. There were 20 males and 16 females with an average age of 45 years old (ranged from 20 to 58). Among them, 5 cases were congenital hemivertebrae deformity, 12 cases were secondary to tuberculotic deformity, 14 cases were post-traumatic deformity with pain, 5 cases were ankylosing spondylitis. Low back pain, living ability, scoliotic Cobb angle were analyzed according to VAS scoring, Oswestry Disability Index (ODI), radiological examination. RESULTS: Average operative time was 245 min and average bleeding was 1 900 ml in 36 patients. All patients were followed up more than 1 year and obtained bone fusion at 1 year after operation. Preoperative,postoperative at 1 week and 1 year, VAS scoring was 7.2 +/- 1.4, 2.5 +/- 1.0, 1.8 +/- 0.5, respectively; ODI was (72.50 +/- 10.80)%, (42.50 +/- 11.10)%, (22.50 +/- 7.90)%, respectively; kyphosis Cobb angle was (76.31 +/- 2.52) degrees, (23.66 +/- 1.16) degrees, (23.67 +/- 1.16) degrees, respectively; lumbar scoliosis Cobb angle was (71.86 +/- 4.02) degrees, (30.81 +/- 2.33) degrees, (30.82 +/- 2.32) degrees, respectively. Postoperative at 1 week and 1 year,above data had obviously improved than that of preoperative (P < 0.05); and there was no significant difference in Cobb angle between postoperative at 1 week and postoperative at 1 year (P > 0.05). CONCLUSION: Treatment of thoracolumbar deformity with transpedicular eggshell technique could obtain effective correcting and clinical results.

[Clinical study of posterior transarticular fixation with rod-screw in the lower cervical vertebrae].

OBJECTIVE: To explore the effects of posterior transarticular fixation with rod-screw in treating fracture and dislocation, spinal stenosis of lower cervical vertebrae. METHODS: From July 2005 to July 2009,11 patients with cervical fracture and dislocation and 9 with spinal stenosis of lower cervical vertebrae underwent operation with transarticular fixation with rod-screw (Vertex system). There were 16 cases male and 4 cases female, ranging in age from 29 to 76 years with an average of 51 years. All patients underwent decompression,internal fixation and fusion through posterior approach (combined with anterior approach in 3 cases). The method of insertion of screw: the starting point located in medial 1 mm of the midpoint of the lateral mass, angle in sagittal plane was 15 degrees-20 degrees of caudal clinism and in coronal plane was 35 degrees-40 degrees of external clinism. The position of screws, the cervical array, bone graft and fusion were observed by X-ray films. RESULTS: A total of 88 transarticular screws were successfully inserted, 10 screws located in C3,4, 20 in C4,5, 32 in C5,6, 26 in C6,7. There were no complications related to screw insertion, such as injury of the vertebral artery, nerve roots and the spine cord. All patients obtained bone fusion without internal fixation breaking. The improvement rate of JOA was 55.8% at the 1st week after operation, 5 cases got excellent results, 7 good, 7 fair, 1 poor; the improvement rate of JOA was 74.5%, at the 3rd month after operation, 6 cases got excellent results, 8 good, 6 fair. There was significant difference in the JOA between before operation and at the 3rd month after operation. CONCLUSION: The transarticular screw fixation with rod-screw in the lower cervical spine is an effective fixation, which has advantages of rigid stability, convenience to perform, and can reduce operative risk in initial application, but the long-term follow-up is very necessary.

[Clinical observation of mid-stage complications after cervical disc replacement].

OBJECTIVE: To summarize the therapeutic experience of Bryan prosthetic cervical disc replacement at the 3rd years after operation and to analyze the clinical effect, incidence rate of heterotopic ossification, conditions of prosthetic fusion in order to investigate the countermeasures. METHODS: From December 2005 to December 2008, 54 patients with cervical syndrome (34 males and 20 females, the age was from 39 to 69 years with an average of 50.5) were treated with single level Bryan prosthetic cervical disc replacement. The patients were followed for 24-36 months with an average of 30 months. The symptoms and nerve function were evaluated according to JOA and Odom's scoring. The anterior-posterior and lateral cervical X-ray films were also taken regularly every three months for the observation of heterotopic ossification and prosthetic fusion. Meanwhile, the X-ray films of the forward bending, extending, left and right lateriflection were taken before operation and at the 1st years after operation for the measurement of the stability and rang (ROM) of replaced levels. RESULTS: The pain symptom and neurological function of all 54 patients were improved obviously. JOA score increased with an average of 76.1%, and ROM of replaced levels also improved obviously. The incidence rate of heterotopic ossification and prosthetic fusion went up year by year, 3.7% (2/54) for the first year, 16.7% (9/54) for the second year and 22.2% (12/54) for the nearly third year. CONCLUSION: Bryan prosthetic cervical disc replacement has better mid-stage results than conventional methods. Modified surgical methods and early rehabilitation exercise may reduce the relatively high incidence rate of heterotopic ossification and prosthetic fusion.