Influence of Cage Design on Radiological and Clinical Outcomes in Dorsal Lumbar Spinal Fusions: A Comparison of Lordotic and Non‐Lordotic Cages

ObjectivesTo evaluate the comparison between lordotic and non‐lordotic transforaminal lumbar interbody fusion (TLIF) cages in degenerative lumbar spine surgery and analyze radiological as well as clinical outcome parameters in long‐term follow up.MethodsIn a retrospective study design, we compared 37 patients with non‐lordotic cage (NL‐group) and 40 with a 5° lordotic cage (L‐group) implanted mono‐ or bi‐segmental in TLIF‐technique from 2013 to 2016 and analyzed radiological parameters of pre‐ and postoperative (Lumbar lordosis (LL), segmental lordosis (SL), and pelvic tilt (PT), as well as clinical parameters in a follow‐up physical examination using the Oswestry disability index (ODI), Roland–Morris Score (RMS), and visual analog scale (VAS).ResultsSurgery was mainly performed in lower lumbar spine with a peak in L4/5 (mono‐segmental) and L4 to S1 (bi‐segmental), long‐term follow‐up was on average 4 years postoperative. According to the literature, we found significantly better results in radiological outcome in the L‐group compared to the NL‐group: LL increased 6° in L‐group (51° preoperative to 57° postoperative) and decreased 1° in NL‐group (50° to 49° (P < 0.001). Regarding SL, we found an increase of 5° in L‐group (13° to 18°) and no difference in NL‐group (15°)(P < 0.001). In PT, we found a clear benefit with a decrease of 2° in L‐group (21° to 19°) and no difference in NL‐group (P = 0.008).In direct group comparison, ODI in NL‐group was 23% vs 28% in L‐group (P = 0.25), RMS in NL‐group was 8 points vs 9 points in L‐group (P = 0.48), and VAS was in NL‐group 2.7 vs 3.2 in L‐group (P = 0.27) without significant differences.However, the clinical outcome in multivariate analysis indicated a significant multivariate influence across ODI and RMS of BMI (Wilks λ = 0.57, F [4, 44] = 3.61, P = 0.012) and preoperative SS (Wilks λ = 0.66, F [4, 44] = 2.54, P = 0.048). Age, gender, cage type and postoperative PT had no significant influence (P > 0.05). Intraoperatively, we saw three dura injuries that could be sutured without problems and had no consequences for the patient. In the follow‐up, we did not find any material‐related problems, such as broken screws or cage loosening, also no pseudarthrosis.ConclusionIn conclusion, we think it''s not cage design but other influenceable factors such as correct indication and adequate decompression that lead to surgical success and the minimal difference in the LL therefore seemed to be of subordinate importance.     

Comparisons between Direct Anterior Approach and Lateral Approach for Primary Total Hip Arthroplasty in Postoperative Orthopaedic Complications: A Systematic Review and Meta‐Analysis

The direct anterior approach (DAA) are attracting increasing attention from orthopedic arthroplasty surgeons, due to the less blood loss, mild soft tissue invasion, rapid rehabilitation and shorter length of stay. However, the longer learning curve in DAA can give rise to several complications, such as intraoperative femoral fracture, lateral femoral cutaneous nerve injury, wound‐healing problem, premature revision and so on. This meta‐analysis was performed to compare the rate of postoperative orthopedic complications between the DAA and the lateral approach (LA). All studies involving the comparison of postoperative orthopedic complications after THA between the DAA and LA group were searched in 7 databases prior to October 2020. The odds ratio (OR) with the 95% confidence intervals (CI) for each outcome was calculated by using the RevMan 5.3. The methodological bias of included studies was evaluated and the potential heterogeneity sources were analyzed. Thirteen comparative studies including a total of 24853 hips (9575 hips in the DAA group and 15278 hips in the LA group) were eligible for this meta‐analysis. There was no significant difference in the rate of surgical site infection [2.59% vs 2.14% (OR = 0.98; 95% CI: 0.59‐1.61, P = 0.93)], heterotopic ossification [12.16% vs 26.47% (OR = 0.46; 95% CI: 0.20‐1.07, P = 0.07)] and reoperation [2.70% and 2.11% respectively (OR = 0.93; 95% CI: 0.68‐1.26, P = 0.64)] between the DAA and LA groups. Although a lower rate in prosthesis malposition [36.19% vs 54.86% (OR = 0.50; 95% CI: 0.35‐0.73, P = 0.0003)], leg length discrepancy [1.87% vs 2.37% (OR = 2.35; 95% CI: 1.30‐4.25, P = 0.005)] and Trendelenburg gait [1.68% vs 4.78% (OR = 0.29; 95% CI: 0.13‐0.65, P = 0.003)] was observed in the DAA group, a higher rate in dislocation [0.77% vs 0.18% (OR = 3.73; 95% CI: 2.35‐5.94, P< 0.00001)], periprosthetic fracture [1.05% vs 0.41% (OR = 2.38; 95% CI: 1.58‐3.58, P< 0.0001)], prosthesis loosening [0.61% vs 0.37% (OR = 1.66; 95% CI: 1.05‐2.62, P = 0.03)] and nerve injury [0.95% vs 0% (OR = 7.12; 95% CI: 1.66‐30.48, P = 0.008)] was found in the DAA group. This meta‐analysis demonstrated several evidences indicating that the DAA exhibited the advantages in the accurate prosthesis placement and less damage of surrounding hip musculature. However, a higher rate in dislocation, periprosthetic fracture, prosthesis loosening and nerve injury in the DAA group should be paid more attention, due to the limited exposure and a longer learning curve, compared to the LA.     

Analgesic Effects of Ultrasound‐Guided Iliohypogastric/Ilioinguinal Nerve Block Combined with Lateral Femoral Cutaneous Nerve Block in Total Hip Arthroplasty via Direct Anterior Approach: A Retrospective Cohort Study

ObjectiveThis study aimed to explore the efficacy and safety of the combination of lateral femoral cutaneous nerve blocks (LFCNB) and iliohypogastric/ilioinguinal nerve blocks (IHINB) on postoperative pain and functional outcomes after total hip arthroplasty (THA) via the direct anterior approach (DAA).MethodsIn this retrospective cohort study, patients undergoing THA via the DAA between January 2019 and November 2019 were stratified into two groups based on their date of admission. Sixty‐seven patients received LFCNB and IHINB along with periarticular infiltration analgesia (PIA) (nerve block group), and 75 patients received PIA alone (control group). The outcomes included postoperative morphine consumption, postoperative pain assessed using the visual analogue scale (VAS), the QoR‐15 score, and functional recovery measured as quadriceps strength, time to first straight leg rise, daily ambulation distance, and duration of hospitalization. The Oxford hip score and the UCLA activity level rating were assessed at 1 and 3 months after surgery. In addition, postoperative complications were recorded. Patients were also compared based on the type of incision used during surgery (traditional longitudinal or “bikini” incision).ResultsPatients in the nerve block group showed significantly lower postoperative morphine consumption, lower resting VAS scores within 12 h postoperatively, lower VAS scores during motion within 24 h postoperatively, and better QoR‐15 scores on postoperative day 1. These patients also showed significantly better functional recovery during hospitalization. At 1‐month and 3‐month outpatient follow up, the two groups showed no significant differences in Oxford hip score or UCLA activity level rating. There were no significant differences in the incidence of postoperative complications. Similar results were observed when patients were stratified by type of incision, except that the duration of hospitalization was similar.ConclusionCompared to PIA alone, a combination of LFCNB and IHINB along with PIA can improve early pain relief, reduce morphine consumption, and accelerate functional recovery, without increasing complications after THA via the DAA.     

Learning Curve of Total Hip Arthroplasty in Direct Anterior Approach without Requiring Corrective Osteotomy for Hip Dysplasia

ObjectiveTo explore the learning curve of total hip arthroplasty in direct anterior approach (DA‐THA) without requiring corrective osteotomy for patients with unilateral developmental dysplasia of the hip (DDH) through the evaluation of clinical and radiographic results.MethodFrom December 2015 to January 2021, we retrospectively evaluated a surgeon''s first 100 patients with unilateral hip dysplasia (Crowe I‐III) who underwent DA‐THA. All procedures were performed by a fellowship‐trained joint surgeon. Cementless hemispheric porous‐coated acetabular cups and tapered cementless stems were used in all hips. The radiographic data, including leg length, the height of the center of rotation, femoral head offset, the cup anteversion and inclination angle, were measured. The cumulative sum analysis (CUSUM) and risk‐adjusted cumulative sum analysis (RA‐CUSUM) were used to determine the learning curve of DA‐THA for each patient''s operation time. By analyzing the operation time, complication rate, postoperative length of hospitalization and creatine kinase (before surgery and the third day after surgery), estimated blood loss, Harris score, radiographic data were compared between the different stages of the learning curve.ResultsThe mean follow‐up time was 35.45 ± 16.82 months. The CUSUM method obtained the maximum turning point of the curve at 43 cases, which divided the learning curve into Learning Period and Mastery Period. The CUSUM learning curve was best modeled as a cubic curve with the equation: CUSUM (min) = 0.001x ³ − 0.495x² + 33.60x − 10.00, which had a higher R ² value of 0.967. The pre‐operative data, creatine kinase, estimated blood loss and postoperative Harris scores of the two stages were not statistically significant (P > 0.05). The mean operation time was 118 min in the Learning Period and 87 min in the Mastery Period. Statistically significant differences were detected in the operation time (P < 0.001), postoperative length of hospitalization(P = 0.024), and postoperative leg length discrepancy (P = 0.012) between the two stages. The overall complication rates were 27.9% in the Learning Period and 12.3% in the Mastery Period (p = 0.049). The overall outliers of radiographic data were 34 cases in the Learning Period and 31 cases in the Mastery Period (79.07% vs 54.39%, P = 0.010).ConclusionsThe DA‐THA is a valuable alternative to achieve satisfactory clinical results for mild‐to‐moderate DDH patients. Furthermore, accurate analysis of the learning curve of DA‐THA for hip dysplasia by the CUSUM method showed that the surgeons need to finish about 43 cases to master the technique.     

Posteromedial Corner Release with the Knee in Figure‐of‐Four Position vs Conventional Position for Varus Knee Arthroplasty

ObjectiveTo introduce posteromedial corner release with the knee in the figure‐of‐four position versus the conventional position for varus knee arthroplasty.MethodsThis is a retrospective study. From March 2015 to September 2019, a series of 123 patients (139 knees) with varus knee were randomly and blindly allocated to experimental group (60 patients; 68 knees) and control group (57 patients; 65 knees). Patients in experimental group underwent posteromedial corner release with the knee in the figure‐of‐four position; and patients in control group with the knee in the conventional position. If soft tissue balance was not completely achieved or the medial gap was still tight, an additional loosening technique were used to achieve symmetric medial and lateral space in both groups. Time for soft tissue balancing was defined as the time from the start of the spacer test to the end of the balance test. Length of release was defined as the distance from the osteotomy surface of the tibial plateau to the farthest structures released. The rating system of Hospital for Special Surgery (HSS) knee score was used to evaluate the clinical results. Quantitative variables were described as mean and standard deviation, and compared by one‐way analysis of variance.ResultsThe mean age of experimental group and control group was 70.2 ± 8.7 years and 68.7 ± 6.2 years, respectively (P > 0.05). Preoperatively, the mean HSS score of the groups was 38.2 ± 11.3 and 39.1 ± 10.7, respectively (P > 0.05). The mean varus knee angle was 19.7° ± 9.3° and 19.3° ± 10.7°, respectively (P > 0.05). The mean time for soft tissue balancing was 8.4 ± 3.3 min and 11.3 ± 6.9 min in experimental and control group, respectively (P < 0.05). The mean length of releasing posteromedial corner structures was 35.5 ± 13.4 mm and 27.3 ± 9.7 mm in experimental and control group, respectively (P < 0.05). Additional special loosening techniques were performed in eight knees in experimental group and seven knees in control group. The HSS scores 5 years after surgery were 95.1 ± 16.9 and 94.8 ± 17.2 respectively (P > 0.05). No complications were found during the follow‐up time, and the clinical symptoms were observed to be significantly improved in the patients.ConclusionThe posteromedial corner can be released more extensively and thoroughly when the knee is placed in the figure‐of‐four position during varus knee arthroplasty.     

Expansion of Spinal Canal with Lift‐Open Laminoplasty: A New Method for Compression Cervical Myelopathy

ObjectiveThis study is to introduce lift‐open laminoplasty and verify the increase of the spinal canal area following this surgical technique according to the preoperative anatomical measurement.MethodsThere are 82 patients (43 male and 39 female) analyzed in our study from January 2019 to December 2020. The average age was 63.2 ± 3.21 years (from 41 to 84 years). All of them were treated with open‐door laminoplasty, with a decompression segment range from C3 to C6. The increase of the spinal canal area after open‐door laminoplasty was measured on postoperative CT images of the patients, and the distances between both lamina‐facet junctions and lamina length was measured on preoperative CT images. Using the Pythagorean theorem for the equation of calculation area after the expansile open‐door laminoplasty. Based on previous measurement parameters, spinous process length, lateral mass width, distance between osteotomy line and lamina‐facet junctions line were additionally measured on preoperative CT images. Pythagorean theorem was used for calculating the area after the expansile lift‐open laminoplasty. The results were recorded and a statistical analysis was undertaken. Then, there were six patients (five male and one female) treated with lift‐open laminoplasty on C6, open‐door on C3–C5, who suffer from cervical spondylotic myelopathy from December 2020 to January 2021. The average age was 60.3 ± 1.7 years (from 56 to 71 years). Operation time, blood loss, and Japanese Orthopaedic Association (JOA) score recovery rate were recorded. Intraoperative and postoperative complications were observed.ResultsThe increase of the spinal canal area after open‐door laminoplasty measured on postoperative CT images was 123.01 ± 17.06 mm² and the calculation of the increase of the spinal canal areausing the Pythagorean theorem after open‐door laminoplasty was 122.86 ± 15.86 mm². A comparison of the actual value with calculative value showed no significant difference (T value = 0.057, P value = 0.955). The calculation of the increase of the spinal canal area after lift‐open laminoplasty was 183.57 ± 62.99 mm², which was larger than that after open‐door laminoplasty (T value = 8.462, P value < 0.001). Mean operation time was 153.3 min and operative blood loss was 600 mL of the six patients treated with lift‐open laminoplasty. At 1 month follow‐up, all patients had recovered well. JOA score recovery rate was 37.6% and no intraoperative and postoperative complications occurred.ConclusionLift‐open laminoplasty could preserve nearly 100% of extensor muscle, avoid damaging C7 paraspinal muscles and C6‐7 posterior muscle‐ligament complex, reconstruct the spinous process firmly in the midline, and expand adequate spinal canal area after operation. These advantages could reduce the incidence rate of complications and bring better clinical results than traditional laminoplasty.     

The Clinical Effect of Manual Reduction Combined with Internal Fixation Through Wiltse Paraspinal Approach in the Treatment of Thoracolumbar Fracture

ObjectiveTo evaluate the clinical outcome of manual reduction combined with pedicle fixation through Wiltse paraspinal approach (WPA) in the treatment of thoracolumbar fractures.MethodsFrom May 2017 to May 2019, 48 thoracolumbar fractures patients without neurological symptoms were enrolled in this study. Forty‐eight patients were randomly divided into two groups based on the different surgical treatment. Group 1 was manual reduction combined with pedicle screw fixation through Wiltse paraspinal approach treatment group. Group 2 was pedicle screw fixation through traditional posterior approach treatment group. The operation time (OT), intraoperative blood loss (BL), postoperative drainage (PD), time of brace (TB) and the cobb angle recovery of the injured kyphosis in the prone position were obtained and compared between the two groups, respectively. Comparison of cobb angle changes, serum creatine kinase (CK) level, pain visual analogue score (VAS), Oswestry disability index (ODI), and multifidus cross‐sectional (MCS) area changes were achieved between the two groups, respectively.ResultsForty‐eight patients were enrolled in this study and each group had 24 patients. There was no significant difference between the two groups in patient''s age, height, weight, and body mass index (BMI). There were 20 males and four females in group 1. The mean age, height, weight, and BMI of patients were 61.99 ± 11.00 years (range, 42–75 years), 175.21 ± 4.49 cm, 76.71 ± 4.87 kg, and 24.98 ± 1.03 kg/m² in group 1, respectively. Group 2 had 18 males and six females, and the mean age, height, weight, and BMI of patients were 57.95 ± 9.22 years (range, 44–77 years), 176.37 ± 4.56 cm, 77.42 ± 4.61 kg, and 24.87 ± 1.10 kg/m² in group 2, respectively. The mean bleeding volume of group 1 was significantly less than group 2 (64.13 ± 9.77 ml and 152.13 ± 10.73 ml, respectively) (P < 0.05). The mean operation time, postoperative drainage, and time of brace were 62.95 ± 9.80 min, 66.25 ± 12.75 ml, and 3.62 ± 0.97 days in group 1, respectively, and they were significantly better than those of group 2 (69.29 ± 6.82min, 162.96 ± 14.55ml and 7.88 ± 1.94 days, respectively) (P < 0.05). The mean multifidus cross‐sectional area was significantly smaller than per‐operation after surgery in two groups (P < 0.05). The mean creatine kinase of group 1 was 403.13 ± 39.78 U/L and 292.12 ± 45.81 U/L at 1 and 3 days after surgery, respectively, which was significantly smaller than those in group 2 (654.25 ± 53.13 U/L and 467.67 ± 44.25 U/L, respectively) (P < 0.05). The Oswestry disability index of group 1 were significantly better than those in group 2 especially at 1 month and final follow‐up after surgery (P < 0.05). Moreover, group 1 also had better outcomes in postoperative Cobb angle change than those in group 2, with significant difference on intra‐operation, 1 day and 1 month post‐operation (P < 0.05).ConclusionIn short, this operation is suitable for thoracolumbar fractures without neurologic symptoms. Preoperative manual reduction had advantages of restoring the height of injured vertebrae. Wiltse intermuscular approach can reduce intraoperative blood loss, shorten operation time, and reduce paraspinal muscle damage. Using the traditional posterior approach, it is easy for surgeons to grasp this technique and it should be recommended as conforming with the minimally invasive approach of recent years.     

Percutaneous Endoscopic Lumbar Discectomy via Transforaminal Approach Combined with Interlaminar Approach for L4/5 and L5/S1 Two‐Level Disc Herniation

ObjectiveThe purpose of the present study was to discuss a new surgical strategy that combines percutaneous endoscopic transforaminal discectomy (PETD) with percutaneous endoscopic interlaminar discectomy (PEID) for L4/5 and L5/S1 two‐level disc herniation.MethodsThis was a retrospective study. A total of 19 patients with L4/5 and L5/S1 two‐level lumbar disc herniation (LDH) who underwent percutaneous endoscopic lumbar discectomy (PELD) in our hospital from January 2015 to June 2016 were retrospectively examined. The average age of these 19 patients was 42.21 ± 14.88 years old, including 12 men and 7 women. One experienced surgeon who had carried out more than 3000 lumbar surgeries performed PELD for these patients. During the PELD surgery, the transforaminal approach was adopted for L4/5 level disc herniation and the interlaminar approach was adopted for L5/S1 level disc herniation. The demographic data, operation time (min), fluoroscopy times, hospital stay (days), and complications were recorded and analyzed. The visual analogue scale (VAS), Oswestry disability index (ODI) scores, and the modified MacNab criteria were used to evaluate the surgical outcomes. MRI was conducted to evaluate the radiographic improvement.ResultsAll patients underwent PELD via the transforaminal approach combined with the interlaminar approach successfully and achieved satisfactory efficacy. The follow‐up points were 3, 12, and 18 months. The average hospital stay (days) and the average follow up (months) were 3.32 ± 0.98 and 18.63 ± 3.84, respectively. The operation time and fluoroscopy times were 85.79 ± 12.90 min and 39.05 ± 4.59 times, respectively. The fluoroscopy times (frequency) for L4/5 and L5/S1 were 26.95 ± 6.41 and 12.11 ± 3.49 (t = 7.00, P < 0.05). Furthermore, there was no significant difference for fluoroscopy times between male and female patients (t = 0.89, P = 0.99). The preoperative back pain (VAS‐Back) and the last follow‐up VAS‐Back were 5.58 ± 2.01 and 2.37 ± 1.01, respectively (t = 7.14, P < 0.05). The preoperative leg pain (VAS‐Leg) and the last follow‐up VAS‐Leg were 7.00 ± 1.56 and 1.63 ± 1.01, respectively (t = 20.97, P < 0.05). There were significant differences between preoperative VAS‐Back and the last follow‐up VAS‐Back in men (t = 4.61, P < 0.05) and women (t = 6.57, P < 0.05). In addition, there was significant differences between preoperative VAS‐Leg and the last follow‐up VAS‐Leg in men (t = 13.48, P < 0.05) and women (t = 26.87, P < 0.05). There were significant differences between preoperative ODI scores (44.84 ± 10.82%) and the last follow‐up ODI scores (11.12 ± 5.80%) (t = 10.92, P < 0.05). Preoperative ODI scores and the last follow‐up ODI scores were significantly different for men (t = 8.80, P < 0.05) and women (t = 6.63, P < 0.05). All patients received significant pain relief and functional improvement after the surgery. Except for two cases of postoperative dysesthesia and one dural tear, no severe complications occurred. The dysesthesia symptoms of these two patients disappeared within 1 week with the application of dexamethasone and neurotrophic drugs and the dural tear case also recovered well as the dural laceration was small. No poor results were reported and 89.47% of patients achieved excellent or good recovery.ConclusionPercutaneous endoscopic lumbar discectomy via the transforaminal approach combined with the interlaminar approach under epidural anesthesia can treat L4/5 and L5/S1 two‐level disc herniation safely and effectively.     

Psychological and Functional Comparison between Minimally Invasive and Open Transforaminal Lumbar Interbody Fusion for Single‐Level Lumbar Spinal Stenosis

ObjectiveThe aim of this study was to investigate whether treatment with minimally invasive transforaminal lumbar interbody fusion (Mis‐TLIF) causes patients suffering from lumbar spinal stenosis (LSS) to experience less anxiety and better clinical efficacy than open transforaminal lumbar interbody fusion (TLIF).MethodsIn this retrospective cohort study, we analyzed 86 patients, including 46 male patients and 41 female patients, who suffered from single‐segmental lumbar spinal stenosis in our department between January 2016 and January 2018. They were divided into two groups: a control group (n = 46), for patients who underwent open TLIF surgery, and an experimental group (n = 40), for patients who underwent Mis‐TLIF surgery. All patients were evaluated based on operation time, intraoperative blood loss, hospital stay, visual analogue scale (VAS), Oswestry disability index (ODI), hospital anxiety depression scale (HADS), fusion rate, and complications (screw misplacement and loosening, cerebrospinal fluid leakage, infection, and delayed wound healing). Patient characteristics were compared within and between groups.ResultsThe average incision length was 3.64 ± 0.476 cm in the experimental group, which was smaller than that (8.11 ± 2.406 cm) in the control group (P < 0.05). The operation time of the experimental group was a little longer than that of the control group. The intraoperative blood loss and hospital stay in the experimental group were less than those in the control group.The mean preoperative low back pain VAS score was 7.525 ± 1.432 in the experimental group and 7.087 ± 1.799 in the control group (P > 0.05). The low back pain VAS scores on postoperative day 3 and at 3, 6, and 12 months postoperatively were 5.000 ± 0.987, 4.075 ± 0.997, 2.150 ± 0.834, and 1.450 ± 0.639 in the experimental group, respectively; these scores were lower than those in the control group (6.870 ± 1.572, P < 0.05; 4.630 ± 1.103, P < 0.05; 2.630 ± 1.103, P < 0.05; and 2.326 ± 1.034, P < 0.05, respectively). There was no obvious difference in the leg pain VAS scores between the two groups at all follow‐up points.The mean preoperative ODI score was 58.700% ± 19.703% in the experimental group and 61.696% ± 17.583% in the control group (P > 0.05). The ODI scores at postoperative months 3, 6, and 12 were 25.225% ± 5.554%, 20.150% ± 7.698%, and 16.125% ± 9.565% in the experimental group; these scores were lower than those in the control group (49.130% ± 14.805%, P < 0.05; 34.044% ± 15.148%, P < 0.05; and 29.282% ± 132.567%, P < 0.05, respectively).The mean preoperative HADS score was 14.475 ± 3.113 in the experimental group and 13.391 ± 2.824 in the control group (P > 0.05). However, the mean HADS scores on postoperative day 3 in the experimental group was 8.500 ± 2.000, decreasing obviously compared to the preoperative scores (P < 0.05). The mean postoperative HADS score on postoperative day 3 in the control group was 12.734 ± 1.949, which had not decreased significantly compared to the preoperative score (P > 0.05). The HADS scores in the experimental group was lower than that in the control group on postoperative day 3 (P < 0.05).In the correlation analysis, the incision length was correlated to the HADS scores on postoperative day 3 (r = 0.527, P < 0.05). The HADS scores on postoperative day 3 were positively correlated with the low back pain VAS scores on the same day (r = 0.388, P < 0.05). The HADS scores on postoperative day 3were positively correlated with the ODI scores at 3‐month (r = 0.460, P < 0.05), 6‐month (r = 0.429, P < 0.05), and 12‐month follow up (r = 0.349, P < 0.05).Fusion rates were not significantly different between the two groups. There was no screw misplacement and loosening, infection, or delayed wound healing in either group. The cerebrospinal fluid leakage rate in the control group was higher than that in the experimental group.ConclusionPatients undergoing Mis‐TLIF experience less anxiety and have better outcomes than those who undergo open TLIF. The lower level of anxiety experienced by patients undergoing Mis‐TLIF is positively correlated with postoperative VAS and ODI scores.     

Long‐term Radiological and Clinical Outcome after Lumbar Spinal Fusion Surgery in Patients with Degenerative Spondylolisthesis: A Prospective 6‐Year Follow‐up Study

ObjectiveTo assess which radiological alignment parameters are associated with a satisfactory long‐term clinical outcome after performing lumbar spinal fusion for treating degenerative spondylolisthesis.MethodsThis single‐center prospective study assessed the relation between radiological alignment parameters measured on standing lateral lumbar spine radiographs and the patient‐reported outcome using four different questionnaires (COMI, EQ‐5D, ODI and VAS) as primary outcome measures (level of evidence: II). The following spinopelvic alignment parameters were used: gliding angle, sacral inclination, anterior displacement, sagittal rotation, lumbar lordosis, sacral slope, pelvic tilt and pelvic incidence. Furthermore, the length of stay and perioperative complications were documented. Only cases from 2013 to 2015 of low‐grade degenerative lumbar spondylolisthesis (Meyerding grades I and II) were considered. The patients underwent open posterior lumbar fusion surgery by pedicle screw instrumentation and cage insertion. The operative technique was either a posterior lumbar interbody fusion (PLIF) or a transforaminal lumbar interbody fusion (TLIF) performed by three different senior orthopedic surgeons. Exclusion criteria were spine fractures, minimally invasive techniques, underlying malignant diseases or acute infections, previous or multisegmental spine surgery as well as preoperative neurologic impairment. Of 89 initially contacted patients, 17 patients were included for data analysis (11 males, six females).ResultsThe data of 17 patients after mono‐ or bisegmental lumbar fusion surgery to treat low‐grade lumbar spondylolisthesis and with a follow‐up time of least 72 months were analyzed. The mean age was 66.7 ± 11.3 years. In terms of complications two dural tears and one intraoperative bleeding occurred. The average body mass index (BMI) was 27.6 ± 4.4 kg/m² and the average inpatient length of stay was 12.9 ± 3.8 days (range: 8–21). The long‐term clinical outcome correlated significantly with the change of the pelvic tilt (r _s = −0.515, P < 0.05) and the sagittal rotation (r _s = −0.545, P < 0.05). The sacral slope was significantly associated with the sacral inclination (r _s = 0.637, P < 0.01) and the pelvic incidence (r _s = 0.500, P < 0.05). In addition, the pelvic incidence showed a significant correlation with the pelvic tilt (r _s = 0.709, P < 0.01). The change of the different clinical scores over time also correlated significantly between the different questionnaires.ConclusionsThe surgical modification of the pelvic tilt and the sagittal rotation are the two radiological alignment parameters that can most accurately predict the long‐term clinical outcome after lumbar interbody fusion surgery.     

Joint Awareness after Patellofemoral Arthroplasty Evaluated with the Forgotten Joint Score: A Comparison Study

ObjectiveThe aim of the present study was to compare the forgotten joint score (FJS) in patients with isolated patellofemoral osteoarthritis who underwent patellofemoral arthroplasty (PFA) versus those who underwent total knee arthroplasty (TKA) and to analyze the predictors of the FJS after PFA.MethodsFrom January 2014 to December 2017, a retrospective cohort study of 56 consecutive patients with isolated patellofemoral osteoarthritis underwent PFA and were included in the PFA group. The patients in the PFA group were matched in a 1:1 ratio based on age, sex, body mass index (BMI), and follow‐up duration; 56 patients with isolated patellofemoral osteoarthritis underwent cruciate‐retaining TKA (TKA group). The FJS, range of motion of the knee, and Knee Society Score were assessed at 1 and 3 years postoperatively. In addition, the associations between the potential influencing factors (age, sex, BMI, and preoperative Iwano score of the patellofemoral joint) and the FJS were analyzed using multiple linear regression in the PFA group.ResultsThere were no significant differences between the PFA and TKA groups regarding age (P = 0.316), sex (P = 0.832), BMI (P = 0.447), and follow‐up duration (P = 0.625). Postoperatively, the range of motion of the knee and Knee Society Score was significantly higher in the PFA group than the TKA group at both follow‐up points (P < 0.05). The PFA group had a significantly higher mean FJS than the TKA group at 1 year postoperatively (62.9 ± 12.3 vs 54.1 ± 14.2, P = 0.034) and 3 years postoperatively (63.3 ± 14.1 vs 55.6 ± 16.4, P = 0.042). In the PFA group, multiple linear regression analysis showed that older age was positively correlated with the FJS, while a higher BMI was negatively correlated with the FJS.ConclusionThe patients with isolated patellofemoral osteoarthritis who underwent PFA were more likely to forget the artificial joint and, consequently, may experience a higher degree of satisfaction. In addition, we identified two preoperative patient‐related factors (age and BMI) that may predict the FJS after PFA, which might help in chosing the most appropriate operation.     

Application of Neurite Orientation Dispersion and Density Imaging to Evaluate and Predict the Surgical Outcome for Degenerative Cervical Myelopathy

ObjectivesAlthough the neurite orientation dispersion and density imaging (NODDI) has been shown useful to evaluate the spinal cord dysfunction, there are few prospective studies on analyzing the operation recovery of degenerative cervical myelopathy (DCM) disease using NODDI. This study aims to investigate the preoperative evaluation and predictive ability of NODDI in DCM patients who received posterior cervical laminoplasty.MethodsThis prospective study included 55 patients with DCM from January to December 2017. NODDI metrics, including intracellular volume fraction (Vic), isotropic volume fraction (Viso), and orientation dispersion index (ODI) were measured at the maximally compressed (MC) level and the non‐compressed C2 level in each patient at the preoperative and the 3‐ and 6‐month postoperative follow‐up stages. Neurological function was assessed using the modified Japanese Orthopaedic Association (mJOA) scoring system at each stage. Spearman''s correlation and Kendall''s tau‐b correlation were used to analyze the relationship between NODDI metrics and mJOA scores. Wilcoxon signed rank test was used to examine the changes in the NODDI and mJOA scores between the preoperative and 6‐month follow‐up stages. ROC analysis was used to further evaluate the predictive capability.ResultsPreoperative Vic at the level of C2 has a significant correlation with the preoperative mJOA score (r = 0.278, p = 0.048). Vic and Viso at the MC level were significantly different between the preoperative period and 6‐month follow‐up. Viso at the MC level was correlated with the mJOA score at 6‐month follow‐up (r = −0.302, p = 0.044). Vic and ODI at the C2 level predicted the surgical prognosis, with areas under the receiver‐operating characteristic curve of 0.663 (p = 0.042) and 0.716 (p = 0.014).ConclusionsThe preoperative NODDI metrics at the C2 level are capable of evaluating the severity of spinal cord dysfunction and predict the surgical outcome.     

Clinical Results of Acetabular Fracture via the Pararectus versus Ilioinguinal Approach

ObjectiveTo compare the clinical efficacy of pararectus and ilioinguinal approach in the treatment of acetabular fractures.MethodsA retrospective analysis of the clinical data of 60 patients with acetabular fractures treated by the pararectus approach or the ilioinguinal approach from January 2016 to January 2019 was performed to record all data by comparing the length of the surgical incision, the time to expose the fracture and the amount of blood loss during the operation. Patients were routinely followed up at 1, 6 and 12 months postoperatively. The function of the hip joint after the operation (Improved Merle d'' Aubigne and Postel scores) and the complications postoperation were recorded.ResultsThere was a significant difference (mean ± SD) in the length of surgical incision [(11.2 ± 1.5) cm vs.(23.8 ± 2.1) cm], and in surgical exposure time [(10.8 ± 1.7) min vs.(19.9 ± 1.9) min] (P < 0.05) between the two approaches; there was no significant difference (mean ± SD) in intraoperative blood loss [(591.8 ± 131.4) mL vs. (614.6 ± 132.7) mL] or in hip function scores at the last follow‐up between the two groups (P > 0.05). In the pararectus approach group, there was one patient (3.3%) with postoperative wound fat liquefaction, and the wound completely improved by secretion culture, enhanced dressing and effective antibiotics, one patient (3.3%) developed lateral femoral cutaneous nerve injury; One case (3.3%) of postoperative myositis ossificans occurred in the ilioinguinal approach group, and there were no obvious symptoms.ConclusionsThese data suggest that for patients with acetabular fractures, both the pararectus approach and the ilioinguinal approach can achieve satisfactory surgical results, but the former has relatively simple operation and small incision length, which is in line with the modern concept of the minimally invasive pelvis.     

Comparison of the Curative Effect of Percutaneous Reduction with Plastic Calcaneal Forceps Combined with Medial External Fixation in the Treatment of Intra‐Articular Calcaneal Fractures

ObjectiveTo compare the clinical efficacy of percutaneous minimally invasive reduction combined with external fixation and a tarsal sinus approach to treat Sanders type II and III intra‐articular calcaneal fractures.MethodsThe clinical data of 64 patients with Sanders type II and III calcaneal fractures admitted to our hospital from January 2010 to January 2016 were retrospectively analyzed; data includedage, sex, body mass index. According to the surgical method, they were divided into the percutaneous minimally invasive reduction with internal and external fixation group (30 cases) and the tarsal sinus approach group (34 cases).The two groups of patients were compared in terms of the time tosurgery, length of hospital stay, intraoperative blood loss, operative duration, complications, radiographic features, including the heel bone length, width, height, Bohlerangle, Gissane angle, and calcaneal varus angle, and clinical efficacy indicators, including the American Orthopedic Foot and Ankle Society (AOFAS) score, the visual analog scale (VAS) pain score, health survey profile (SF‐36) score and Maryland ankle function score.ResultsPatients in both groups were followed up for 12 to 50 months, with an average of 24.8 months.Bony union was achieved in all cases. The time to surgery, length of hospitalstay, intraoperative blood loss and incidence of incision‐related complications were significantly lower in the percutaneous minimally invasive medial external fixation group than in the tarsal sinus group (P < 0.01). At the last follow‐up, the calcaneal length, width, and height, Bohler angle, Gissane angle, and varus angle were significantly increased in both groups (P < 0.01), the calcaneal width was significantly lower after than before surgery (P < 0.01), and there were no statistically significant differences between the two groups (P > 0.05). As measures of clinical efficacy, the AOFAS, VAS, SF‐36 and Maryland scores were 85.28 ± 8.21, 0.84 ± 1.21, 82.95 ± 3.25 and 83.56 ± 3.32, respectively, at the last follow‐up in the percutaneous minimally invasive medial external fixation group and 83.32 ± 7.69, 1.85 ± 1.32, 80.71 ± 5.42, and 81.85 ± 2.41 in the tarsal sinus group, respectively, with no significant differences between the two groups (P > 0.05).ConclusionUnder the condition of a good command of surgical indications and surgical skills, the use of plastic calcaneal forceps for percutaneous minimally invasive reduction combined with medial external fixation for the treatment of Sanders type II and III intra‐articular calcaneal fractures can achieve similar clinical effects as the tarsal sinus approach. However, the use of plastic calcaneal forceps for percutaneous minimally invasive reduction combined with internal and external fixation has advantages, such as fewer complications, less bloodloss, and a shorter operation, and thus has good safety and is worthy of clinical promotion.     

Anterior Cervical Discectomy and Fusion Combined with Foraminotomy Assisted by High‐Definition 3‐Dimensional Exoscope in the Treatment of Cervical Spondylotic Radiculopathy Secondary to Bony Foraminal Stenosis

ObjectiveTo evaluate the outcomes of cervical spondylotic radiculopathy secondary to bony foraminal stenosis treated with anterior cervical discectomy and fusion (ACDF) combined with anterior cervical foraminotomy (ACF) assisted by High‐Definition 3‐Dimensional Exoscope.MethodsIn this retrospective study, a total of 19 consecutive patients (12 males and seven females, with an average of 49.2 years, range from 40 to 59 years) with spondylotic radiculopathy caused by bony foraminal stenosis underwent ACDF combined with ACF assisted by High‐Definition 3‐Dimensional Exoscope in our hospital between January 2019 and December 2019 were included in this study. All patients signed the consent form before the surgery. The patient baseline information such as gender, age, body mass index (BMI), surgery time, blood loss, hospital stay, lesion segment, side, follow‐up time and postoperative complications were recorded. The Japanese Orthopedic Association (JOA), Neck Disability Index (NDI), and Visual Analogue Scale (VAS) were measured and compared before surgery, 1 months and final follow‐up after surgery. The radiographic outcomes were evaluated using the C₂‐C₇ angel, disc height, foraminal height, superior diagonal distance, inferior diagonal distance, and foraminal area.ResultsThe involved levels included C₄‐C₅ (six cases), C₅‐C₆ (10 cases), C₆‐C₇ (three cases). The mean duration of the surgery, mean blood loss, mean hospital stay, and mean follow‐up were 100 ± 11.10 min, 19.4 ± 7.05 mL, 7.1 ± 0.99 days, and 12.1 ± 2.25 months, respectively. The average preoperative JOA score was 11.9 ± 1.31, then improved to 15.7 ± 0.73 (t = −13.45, P < 0.001) and 16.2 ± 0.74 (t = −14.39, P < 0.001) at 1 month after operation and at last follow‐up, respectively. The average preoperative NDI score was 27.3 ± 3.36, then decreased to 5.1 ± 1.79 (t = 20.63, P < 0.001) and 4.5 ± 1.21 (t = 25.53, P < 0.001) 1 month after operation and at last follow‐up, respectively. The average preoperative VAS score was 6.7 ± 0.93, then decreased to 2.4 ± 0.69 (t = 15.05, P < 0.001) and 1.9 ± 0.78 (t = 16.40, P < 0.001) 1 month after operation and at last follow‐up, respectively. As compared with the condition before surgery, there was a significant improvement in the C₂‐C₇ angel, disc height, foraminal height, and foraminal area (P < 0.05). None of the patients developed postoperative vascular injury, nerve injury, loosening and rupture of the internal fixation, displacement of interbody fusion cage, and pseudarthrosis.ConclusionACDF combined with ACF assisted by High‐Definition 3‐Dimensional Exoscope is effective and safe for the treatment of CSR caused by secondary to bony foraminal stenosis.     

Subclinical Hypothyroidism Affects Postoperative Outcome of Patients Undergoing Total Knee Arthroplasty

ObjectiveThe aim of this study was to investigate whether subclinical hypothyroidism could increase the risk of postoperative complications in patients undergoing primary total knee arthroplasty (TKA).MethodsA prospective case‐control study of 796 patients undergoing primary TKA between January 2015 and January 2020 was performed. A total of 700 patients (87.9%) were female and the average age of included patients was 65.0 years, with a standard deviation of 5.6. The participants who had subclinical hypothyroidism were referred to as the case group, while those without abnormal thyrotropin (TSH) were included in the control group (matched for age and gender). The fasting plasma levels of TSH were tested in the morning in all patients. The diagnosis of subclinical hypothyroidism was completed by a senior endocrinologist based on laboratory tests; namely, a serum TSH ≥ 5 mu/L and normal free thyroxine (FT4). Subclinical hypothyroidism was further described as mild (TSH < 10 mu/L) or severe (TSH ≥ 10 mu/L). The incidence of 90‐day postoperative complications was compared between two cohorts. Logistic regression analysis was used for the risk factors of 90‐day postoperative complications following TKA.ResultsA total of 398 patients had a diagnosis of subclinical hypothyroidism. Among them, 275 cases (69.1%) were described as mild (79 patients [19.8%] with low FT4 and 196 patients [49.2%] with normal FT4 in the repeated test) and 123 cases (30.9%) as severe subclinical hypothyroidism. Of the 196 patients (49.2%) with mild subclinical hypothyroidism and normal FT4, 63 patients (15.8%) had symptoms before surgery. Patients were followed up for an average duration of 25.4 months (6 to 43 months). A total of 265 patients (66.6%) received preoperative treatment for subclinical hypothyroidism, with an average therapy time of 9.2 months. There were 162 patients (40.7%) with positive autoantibodies to thyroid peroxidase (anti‐TPO). There were no statistically significant differences in baseline data between cohorts (all P > 0.05). As for the cumulative 90‐day outcomes, subclinical hypothyroidism increased the incidences of both medical and surgical complications following primary TKA compared to those without this condition (11.6% vs 7.2%, OR = 1.55, 95% confidence interval [CI] = 1.47–1.62, P < 0.05). Subclinical hypothyroidism caused patients to suffer increased total incidence of readmission within the first 90 days after discharge when compared to those without this condition (20.61% vs 14.15%, OR = 1.45, 95% CI = 1.41–1.49, P < 0.001). Controlling for preoperative and intraoperative variables, the patients with TSH ≥ 10 mu/L and positive anti‐TPO and those without corrected subclinical hypothyroid and thyroid hormone supplementation were more likely to experience postoperative complications within 90 days of TKA.ConclusionSubclinical hypothyroidism might increase the risk of postoperative complications within 90 days of TKA, especially for the patients with TSH ≥ 10 mu/L and positive anti‐TPO and those without corrected subclinical hypothyroid and thyroid hormone supplementation.     

Low Grip Strength Associated with Clinical Outcomes after Total Hip Arthroplasty ‐ A Prospective Case–Control Study

ObjectiveTo assess whether low grip strength (GS) is associated with clinical outcomes after total hip arthroplasty (THA).MethodsA prospective case–control study was designed to assess 231 cases of primary THA between January 1, 2015 to May 1, 2018, at an urban tertiary care hospital. Patients were placed into two cohorts based on preoperative GS levels. Low GS in the present study was defined as GS lower than 26 kg for men and 16 kg for women in the dominant hand. Baseline data were prospectively collected and included patient demographics (age, sex, body mass index [BMI]), the surgeon''s diagnoses, medical history, length of stay, and American Society of Anaesthesiologists'' (ASA) score. Clinical outcomes included surgery‐ and prosthesis‐related variables. The Harris hip score (HHS) and the Short Form Health Survey (SF‐12) were completed at the baseline visit and at 1 and 2 years postoperatively in the outpatient department to assess the hip''s function and quality of life. Differences in baseline data, length of study (LOS), 90‐day postoperative complications, and hospital readmissions were compared. Besides, the correlations between GS and Harris hip score (HHS) and Short Form score (SF‐12) were tested.ResultsA total of 202 participants have completed records for analysis finally. The patients were followed up for an average of 24.8 months postoperatively (24–26 months). Eighty‐two patients (40.6%) had low GS before THA. Patients with low GS were more likely to be female, older, fracture of femoral head or neck as the primary cause, albumin <3.5 g/dL, and have a lower BMI, higher ASA score, increased rates of the pressure sore, blood transfusion, and LOS compared to normal GS (all P < 0.05). Also, patients in the low GS cohort showed a statistically significant increased unplanned hospital readmissions and decreased discharge home compared to normal GS (both P < 0.05). There was an increasing rate of complications between the two cohorts, for cardiac complications, pressure sore after THA, respiratory complications, urinary tract infection, stroke, and DVT (all P < 0.05). A partial correlation test by controlling medical comorbidities and demographic factors was used to determine the correlation between GS and HHS. There was a significant correlation between them (r = −0.673; P = 0.002). A similar condition was detected in the correlation between GS and SF‐12 (r = 0.645; P = 0.001).ConclusionsClinicians should be encouraged to include GS assessment in their evaluation of patients who planned to undergo THA in order to optimize the treatment of high‐risk individuals.     

Comparison of Outcomes between Robot‐Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion and Oblique Lumbar Interbody Fusion in Single‐Level Lumbar Spondylolisthesis

ObjectiveTo compare the safety and effectiveness of robot‐assisted minimally invasive transforaminal lumbar interbody fusion (Mis‐TLIF) and oblique lumbar interbody fusion (OLIF) for the treatment of single‐level lumbar degenerative spondylolisthesis (LDS).MethodsThis is a retrospective study. Between April 2018 and April 2020, a total of 61 patients with single‐level lumbar degenerative spondylolisthesis and treated with robot‐assisted OLIF (28 cases, 16 females, 12 males, mean age 50.4 years) or robot‐assisted Mis‐TLIF (33 cases, 18 females, 15 males, mean age 53.6 years) were enrolled and evaluated. All the pedicle screws were implanted percutaneously assisted by the TiRobot system. Surgical data included the operation time, blood loss, and length of postoperative hospital stay. The clinical and functional outcomes included Oswestry Disability Index (ODI), Visual Analog scores (VAS) for back and leg pain, complication, and patient''s satisfaction. Radiographic outcomes include pedicle screw accuracy, fusion status, and disc height. These data were collected before surgery, at 1 week, 3 months, 6 months, and 12 months postoperatively.ResultsThere were no significantly different results in preoperative measurement between the two groups. There was significantly less blood loss (142.4 ± 89.4 vs 291.5 ± 72.3 mL, P < 0.01), shorter hospital stays (3.2 ± 1.8 vs 4.2 ± 2.5 days, P < 0.01), and longer operative time (164.9 ± 56.0 vs 121.5 ± 48.2 min, P < 0.01) in OLIF group compared with Mis‐TLIF group. The postoperative VAS scores and ODI scores in both groups were significantly improved compared with preoperative data (P < 0.05). VAS scores for back pain were significantly lower in OLIF group than Mis‐TLIF group at 1 week (2.8 ± 1.2 vs 3.5 ± 1.6, P < 0.05) and 3 months postoperatively (1.6 ± 1.0 vs 2.1 ± 1.1, P < 0.05), but there was no significant difference at further follow‐ups. ODI score was also significantly lower in OLIF group than Mis‐TLIF group at 3 months postoperatively (22.3 ± 10.0 vs 26.1 ± 12.8, P < 0.05). There was no significant difference in the proportion of clinically acceptable screws between the two groups (97.3% vs 96.2%, P = 0.90). At 1 year, the OLIF group had a higher interbody fusion rate compared with Mis‐TLIF group (96.0% vs 87%, P < 0.01). Disc height was significantly higher in the OLIF group than Mis‐TLIF group (12.4 ± 3.2 vs 11.2 ± 1.3 mm, P < 0.01). Satisfaction rates at 1 year exceeded 90% in both groups and there was no significant difference (92.6% for OLIF vs 91.2% for Mis‐TLIF, P = 0.263).ConclusionRobot‐assisted OLIF and Mis‐TLIF both have similar good clinical outcomes, but OLIF has the additional benefits of less blood loss, less postoperative hospital stays, higher disc height, and higher fusion rates. Robots are an effective tool for minimally invasive spine surgery.     

Do Radiographic Results of Transforaminal Lumbar Interbody Fusion Vary with Cage Position in Patients with Degenerative Lumbar Diseases?

ObjectiveTo investigate whether the radiographic results are affected by cage position in single‐level transforaminal lumbar interbody fusion (TLIF).MethodBetween January 2016 and June 2018, 130 patients (62 males and 68 females, average age: 55.28 ± 10.11 years) who underwent single‐level TLIF were analyzed retrospectively. Standing lateral radiographs of the lumbar spine were collected and evaluated preoperatively, postoperatively, and at the time of last follow‐up. Cage position in the fused segment was recorded using a central point ratio (CPR), which indicated the cage position. CPR is calculated by dividing the distance between the cage center point and the posterior extent of the superior endplate of the inferior vertebra by the length of the superior endplate of the inferior vertebra. Based on cage positions, the patients were divided into three groups: Anterior Group (n = 38); Middle Group (n = 68); and Posterior Group (n = 24). Segmental lumbar lordosis (SLL), foraminal height (FH), posterior disc height (PDH), and anterior disc height (ADH) were evaluated. A subanalysis was also performed on cage height within each group.ResultsThe average follow‐up time of the patients was 35.20 ± 4.43 months. The mean values of CPR in Anterior Group, Middle Group, and Posterior Group were 0.64, 0.51, and 0.37, respectively. The FH, PDH, and ADH were significantly increased after TLIF in all groups (P < 0.05). There were significant differences in increase of SLL in Anterior Group (4.4°) and Middle Group (3.0°), but not in Posterior Group (0.3°). Furthermore, in the comparison of the three groups, the increase of SLL, FH, and PDH was statistically different (P < 0.05), while not for ADH (P > 0.05). The significant correlations in surgery were: CPR and ΔSLL (r = 0.584, P < 0.001), CPR and ΔFH (r = −0.411, P < 0.001), and CPR and ΔPDH (r = −0.457, P < 0.001). However, ADH had a positive correlation with cage height when the cage was located in anterior and middle of the endplate. Moreover, cage height had a positive correlation with SLL when the cage was located anteriorly and had a negative correlation with SLL when the cage was located posteriorly. FH and PDH both had a positive correlation with cage height in any cage position.ConclusionThe cage located in different positions has different effects on radiographic results in single‐level TLIF. A thicker cage located anteriorly will gain maximum SLL and avoid the reduction of FH and PDH.     

The Effect of Laminectomy with Instrumented Fusion Carried into the Thoracic Spine on the Sagittal Imbalance in Patients with Multilevel Ossification of the Posterior Longitudinal Ligament

ObjectiveTo determine if there is a difference in either the cervical alignment or the clinical outcomes in cervical ossification of the posterior longitudinal ligament (OPLL) patients who underwent laminectomy with instrumented fusion (LIF) ending at C₆, C₇, or proximal thoracic spine for the treatment of multilevel OPLL, and to find out the appropriate distal fusion level.MethodsThis was a single‐center retrospective study. In total, 36 patients with cervical OPLL who underwent three or more level LIF in our institution between January 2015 and January 2017 were enrolled. They were divided into three groups according to their distal ends: C₆ (nine females and 11 males, 60.45 ± 9.68 years old), C₇ (four females and six males, 61.60 ± 10.29 years old), and T‐group (two females and four males, 64.33 ± 8.12 years old). Radiographic (compression level, classification of OPLL, occupying rate, C_2‐7 cobb angle, C_2‐7 sagittal vertical axis, and fusion level) and clinical outcomes (NDI score, operative time, and blood loss) were compared. Predictors of postoperative sagittal imbalance were also identified according to if the postoperative C_2‐7 SVA was greater than 40 mm. The sensitivity and specificity of preoperative parameters predicting postoperative cervical stability were evaluated via the receiver operating characteristic (ROC) curve.ResultsAll patients were followed up at least 1 year. The blood loss in T group was significantly more than C₆ or C₇ group. The length of fusion level became significantly longer when the caudal level extended to the thoracic spine. The age, preoperative SVA, and NDI score at follow‐up were significantly greater in the imbalance group. At the final follow‐up, the cervical lordosis tended to be straight and the C_2‐7 SVA tended to be greater when the caudal level of fusion was extended to upper thoracic segment. Further ROC curve analysis suggested that patients’ age had a sensitivity of 75.00%, specificity of 79.17% for cervical stability, and the AUC was 0.844 (P < 0.01), with the cutoff value for age being 66.5 years old. For preoperative SVA, the sensitivity was 58.30%, and specificity was 91.70%, with the AUC of 0.778 (P < 0.01). The cutoff value for preoperative SVA was 30.4 mm.ConclusionAlthough posterior fusion terminating in the thoracic spine was not superior to the cervical spine for patients with multilevel OPLL, for elderly patients (>67 years) with great preoperative SVA (>30 mm), terminating at C₆ was recommended to limit the invasion of cervical extensor muscles, provided the decompression was adequate.