Characteristics of Screw Perforation and Screw Loosening in Atlantoaxial Transarticular Fixation Using a Preoperative Computed Tomography-Based Navigation System.

BACKGROUND: Atlantoaxial transarticular fixation, also called the Magerl technique, is said to be the most robust biomechanical method of fixation of the atlantoaxial vertebrae. However, the procedure carries a risk of spinal cord and vertebral artery injury during the insertion process, especially in patients with a high-riding vertebral artery. In this study, a computed tomography (CT)-based navigation system was used for preoperative planning and insertion. This investigation sought to determine the rate and direction of screw perforation as well as the incidence of screw loosening in computer-assisted atlantoaxial transarticular fixation. METHODS: Sixty patients (31 men and 29 women; mean ± SD age: 65.3 ± 19.6 years) who received atlantoaxial transarticular screw insertion with preoperative CT navigation were analyzed. We investigated screw position and loosening by CT at the final follow-up. RESULTS: Of the 108 screws inserted, the rate of Grade 2 or higher perforation was 4.6% (5/108). Nine of 81 (11.1%) screws inserted into the 44 patients who were followed for at least 6 months showed loosening. Logistic regression analysis revealed that unilateral insertion (odds ratio: 8.50, 95% confidence interval: 1.53-47.2, P = 0.014) was significantly associated with the incidence of screw loosening. CONCLUSIONS: The screw perforation rate of Grade 2 or higher in computer-assisted atlantoaxial transarticular screw fixation was 4.6%, with comparable frequencies of perforation direction. Unilateral insertion was a significant independent factor associated with screw loosening, which occurred in 11.1% of insertions. CLINICAL RELEVANCE: Spine surgeons should follow up with patients with caution because screws with unilateral insertion are prone to loosening.

Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

PURPOSE: Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. METHODS: A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. RESULTS: Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. CONCLUSIONS: The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.

Real-World Effectiveness of Gelatin-Thrombin Matrix Sealant on Blood Loss in Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion: An Interrupted Time Series Study.

STUDY DESIGN: Retrospective cohort study with interrupted time series analysis. OBJECTIVE: To examine the clinical effectiveness of gelatin-thrombin matrix sealant (GTMS) on blood loss reduction after adolescent idiopathic scoliosis (AIS) surgery. SUMMARY OF BACKGROUND DATA: The real-world effectiveness of GTMS on blood loss reduction in AIS surgery has not been determined. PATIENTS AND METHODS: The medical records of patients receiving AIS surgery were retrospectively collected during a period before GTMS approval at our institution (January 22, 2010-January 21, 2015) as well as during a postintroduction period (January 22, 2015-January 22, 2020). The primary outcomes were intraoperative blood loss, drain output over 24 hours, and total blood loss (intraoperative blood loss + drain output over 24 h). Interrupted time series analysis using a segmented linear regression model was used to estimate the effect of GTMS on blood loss reduction. RESULTS: A total of 179 AIS patients [mean age (range): 15.4 (11-30) yr; 159 females and 20 males; 63 preintroduction patients and 116 postintroduction patients] were included. After its introduction, GTMS was used in 40% of cases. Interrupted time series analysis revealed changes of -340 mL (95% CI: -649 to -31, P = 0.03) for intraoperative blood loss, -35 mL (95% CI: -124 to 55, P = 0.44) for drain output over 24 hours, and -375 mL (95% CI: -698 to -51, P = 0.02) for total blood loss. CONCLUSIONS: The availability of GTMS was significantly associated with reduced intraoperative and total blood loss in AIS surgery. GTMS use as needed is recommended to control intraoperative bleeding in the setting of AIS surgery. LEVEL OF EVIDENCE: 3.

Reliability and validity of gait dynamic balance assessment in adult spinal deformity patients using a two-point trunk motion measuring device.

BACKGROUND CONTEXT: Adult spinal deformity (ASD) patients often complain of walking discomfort. However, dynamic balance evaluation methods of gait in ASD have not been well established. DESIGN: Case series study. PURPOSE: Characterize the gait of ASD patients using a novel two-point trunk motion measuring device. PATIENT SAMPLE: Sixteen ASD patients scheduled for surgery and 16 healthy control subjects. OUTCOME MEASURES: Trunk swing width and track length of the upper back and sacrum. METHODS: Gait analysis was performed using a two-point trunk motion measuring device on 16 ASD patients and 16 healthy control subjects. Three measurements were taken for each subject, and the coefficient of variation was determined to compare measurement accuracy between the ASD and control groups. Trunk swing width and track length were measured in three dimensions for comparisons between the groups. The relationship among output indices, sagittal spinal alignment parameters, and quality of life (QOL) questionnaire scores was examined as well. RESULTS: No significant difference was found for the precision of the device between the ASD and control groups. Compared with controls, the walking style of ASD patients tended to have larger right-left swing of the trunk (+14.0 cm and +23.3 cm at the sacrum and upper back, respectively), larger horizontal plane movement of the upper body (+36.4 cm), less vertical movement (-5.9 cm and -8.2 cm up-down swing at the sacrum and upper back, respectively), and longer gait cycle (+0.13 sec). Regarding QOL in ASD patients, greater right-left/front-back swing of the trunk, greater movement in the horizontal plane, and longer gait cycle were associated with lower QOL scores. Conversely, greater vertical movement was associated with higher QOL. CONCLUSIONS: ASD patients had unique gait characteristics, the intensity of which were associated with diminished QOL. The two-point trunk motion measuring device may be reliable and useful for the clinical assessment of balance during gait in ASD patients.

Frequency and Associated Factors of Postoperative Wound Dehiscence in Posterior Cervical Spine Surgery.

OBJECTIVE: Wound dehiscence after cervical spine surgery is a well-known complication that can be a challenge for spine surgeons to manage, especially in cases of exposed implants. However, few studies have focused primarily on this phenomenon in cervical spine surgery to date. This investigation sought to determine the frequency of wound dehiscence following posterior cervical spine surgery and identify patient-based risk factors. METHODS: The medical data of 405 consecutive patients (290 male and 115 female; mean age: 68.9 years) who underwent posterior cervical spine surgery were retrospectively examined. Logistic regression models were employed to examine the prevalence, characteristics, and risk factors of postoperative wound dehiscence. RESULTS: We observed that 5.2% of cervical spine surgery patients experienced procedural postoperative wound dehiscence. In comparisons of dehiscence and non-dehiscence groups, significant differences were found for posterior instrumented fusion (81.0% vs. 45.3%; P < 0.01), extended T1 fusion (57.1% vs. 12.8%; P < 0.01), occipitocervical fusion (19.0% vs. 6.2%; P = 0.048), fused intervertebral levels (4.0 vs. 1.5; P < 0.01), surgical time (246 minutes vs. 165 minutes; P < 0.01), blood loss volume (228 mL vs. 148 mL; P = 0.023), and dialysis (14.3% vs. 1.8%; P = 0.011). Multivariate analysis identified extended T1 fusion and dialysis to be significantly associated with wound dehiscence with odds ratios of 5.82 and 10.70, respectively. CONCLUSIONS: The observed frequency of postoperative wound dehiscence in cervical spine surgery was 5.2%. As extended T1 fusion and dialysis may increase the risk of dehiscence after surgery, patients who display such risk factors may require additional observation and care.

Impact of Physical Flexibility Changes on Respiratory Function after Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis Surgery.

Introduction: Corrective scoliosis surgery in patients with adolescent idiopathic scoliosis (AIS) increases thoracic volume but does not improve respiratory function (RF). This study evaluates the effect of physical flexibility (PF) improvement after scoliosis surgery on RF. Methods: This study reviewed the records of 61 consecutive patients with AIS (56 female and 5 male; mean±standard deviation age: 14.8±2.2 years, range: 11-20 years) who had undergone posterior spinal fusion (PSF) of the thoracic curve. PF evaluated as finger-floor distance (FFD) was measured preoperatively and one year after surgery. After dividing the cohort into the PF improvement group and the PF nonimprovement group, RF changes at two years postoperative were statistically compared. Using logistic regression analysis, we evaluated the impact of a PF improvement on % forced vital capacity (%FVC) two years after surgery. Results: The rate of patients with increased FVC, %FVC, and forced expiratory volume 1.0 second two years after surgery was 79%, 51%, and 80%, respectively. The PF improvement group exhibited a significantly higher gain in %FVC versus the PF nonimprovement group (P=0.043). Moreover, PF improvement significantly prevented a %FVC decrease (odds ratio 8.43, 95% confidence interval 1.92-59.70; P<0.001), with an adjusted odds ratio of 11.86 (P<0.001). Conclusions: Patients with diminished PF after PSF for AIS may be less likely to achieve postoperative %FVC improvement. As increased postsurgical %FVC had a positive effect on physical function, treatment strategies that focus on maintaining and increasing PF are desirable from an RF viewpoint.

A challenging case of lumbar vertebral burst fracture with alcohol withdrawal delirium: A case report.

BACKGROUND: Delirium tremens is a symptom of alcohol withdrawal syndrome that occurs 48 to 96 hours after the last drink in 5% of withdrawing patients. METHODS: This report describes the clinical progression of a case of lumbar vertebral burst fracture with alcohol withdrawal delirium that was difficult to manage. RESULTS: A 47-year-old man was rushed to our hospital complaining of lumbar back pain and numbness in both lower extremities resulting from a 6-m fall during civil engineering work. Computed tomography (CT) revealed a L1 burst fracture with a highly protruding bone fragment in the spinal canal. Magnetic resonance imaging disclosed significant compression of the conus and intramedullary signal changes. We immediately performed posterior spinal fusion and vertebroplasty using instrumentation. On the 4th postoperative day, he became severely agitated, as diagnosed as having delirium tremens related to alcohol withdrawal syndrome, and soon began appropriate medication with diazepam. Although his symptoms persisted until 6 days postoperatively, follow-up CT detected no evidence of screw loosening or breakage. CONCLUSION: We encountered a patient with severe delirium tremens developing several days after thoraco-lumbar fusion surgery. Prompt internal fixation successfully treated the spinal injury and prevented neurological damage. It may also be necessary to consider treatment strategies for patients with a background of heavy alcohol consumption in consideration of delirium tremens and other symptoms of alcohol withdrawal.

Comparison of spinous process-splitting laminectomy versus posterolateral fusion for lumbar degenerative spondylolisthesis.

BACKGROUND: Although several studies have recently shown that spinous process-splitting laminectomy (SPSL) maintains lumbar spinal stability by preserving posterior ligament components and paraspinal muscles as compared with conventional laminectomy, evidence is scarce on the treatment outcomes of SPSL limited to lumbar degenerative spondylolisthesis. We herein compare the surgical results and global alignment changes for SPSL versus posterolateral lumbar fusion (PLF) without instrumentation for lumbar degenerative spondylolisthesis. METHODS: A total of 110 patients with Grade 1 lumbar degenerative spondylolisthesis who had undergone SPSL (47 patients) or PLF (63 patients) with minimum 1-year follow-up were retrospectively enrolled from a single institutional database. RESULTS: Mean operating time per intervertebral level and intraoperative blood loss per intervertebral level were comparable between the SPSL group and PLF group. Japanese Orthopaedic Association scores, Oswestry disability index, and visual analog scale scores were significantly and comparably improved at 1 year postoperatively in both groups as compared with preoperative levels. The numbers of vertebrae with slip progression to Grade 2 and slip progression of 5% or more at 1 year postoperatively were similar between the groups. In the SPSL group, mean pelvic tilt (PT) was significantly decreased at 1 year postoperatively. In the PLF group, mean lumbar lordosis (LL) was significantly increased, while mean sagittal vertical axis, PT, and pelvic incidence-LL were significantly decreased at 1 year after surgery. CONCLUSIONS: Compared with PLF without instrumentation, SPSL for Grade 1 lumbar degenerative spondylolisthesis displayed comparable results for slip progression and clinical outcomes at 1 year postoperatively.

Tips and pitfalls to improve accuracy and reduce radiation exposure in intraoperative CT navigation for pediatric scoliosis: a systematic review.

BACKGROUND CONTEXT: An increasing number of medical centers are adopting an intraoperative computed tomography (iCT) navigation system (iCT-Navi) to provide three-dimensional navigation for pediatric scoliosis surgery. While iCT-Navi has been reported to provide higher pedicle screw (PS) insertion accuracy, it may also result in higher radiation exposure to the patient. What innovations and studies have been introduced to reduce radiation exposure and further improve PS insertion? PURPOSE: Evaluate the level of evidence and quality of papers while categorizing the tips and pitfalls regarding pediatric scoliosis surgery using iCT-Navi. Compare iCT-Navi with other methods, including preoperative CT navigation. STUDY DESIGN: Systematic review. PATIENT SAMPLE: Articles on pediatric scoliosis surgery with iCT-Navi published through to June 2022. OUTCOME MEASURES: PS perforation rate and patient intraoperative radiation dose. METHODS: Following PRISMA guidelines, the Cochrane Library, Google Scholar, and PubMed databases were searched for articles satisfying the criteria of iCT-Navi use and pediatric scoliosis surgery. The level of evidence and quality of the articles meeting the criteria were evaluated according to the guidelines of the North American Spine Society and American Academy of Orthopedic Surgeons, respectively. The articles were also categorized by theme and summarized in terms of PS insertion accuracy and intraoperative radiation dose. The origins and characteristics of five major classification methods of PS perforation grade were summarized as well. RESULTS: The literature search identified 811 studies, of which 20 papers were included in this review. Overall, 513 pediatric scoliosis patients (381 idiopathic, 44 neuromuscular, 39 neurofibromatosis type 1, 28 congenital, 14 syndromic, seven other) were evaluated for PS perforations among 6,209 iCT-Navi insertions. We found that 232 (3.7%) screws were judged as major perforations (G2 or G3), 55 (0.9%) screws were judged as dangerous deviations (G3), and seven (0.1%) screws were removed. There were no reports of neurovascular injury caused by PSs. The risk factors for PS perforation included more than six vertebrae distance from the reference frame, more than nine consecutive insertions, upper thoracic level, thinner pedicle, upper instrumented vertebra proximity, short stature, and female. The accuracy of PS insertion did not remarkably decrease when the radiation dose was reduced to 1/5 or 1/10 by altering the iCT-Navi protocol. CONCLUSIONS: iCT-Navi has the potential to reduce PS perforation rates compared with other methods. The use of low-dose radiation protocols may not significantly affect PS perforation rates. Although several risk factors for PS perforation and measures to reduce radiation dose have been reported, the current evidence is limited by a lack of consistency in classifying PS perforation and evaluating patient radiation dose among studies. The standardization of several outcome definitions is recommended in this rapidly developing field.

Usefulness of modified S-line for upper instrumented vertebra selection in adolescent idiopathic scoliosis Lenke type 2 curves.

No validated systems exist for selecting the upper instrumented vertebra (UIV) for optimal postoperative shoulder balance in Lenke type 2 adolescent idiopathic scoliosis (AIS). This study evaluated a new method for shoulder balance prediction using the modified Shinshu line (MSL) for UIV selection in AIS Lenke type 2 curves. Fifty-five consecutive AIS patients receiving posterior spinal fusion (PSF) for a Lenke type 2 AIS curve were retrospectively analyzed according to several UIV determination models. Shoulder imbalance was judged as absolute radiographic shoulder height ≥ 10 mm at the 2-year observational endpoint. The MSL was the line between the center of the spinous process of C7 and that of the lowest instrumented vertebra. The vertebral body first touched proximally by the MSL was defined as the MSL vertebra (MSLV) and recommended as the UIV. The group with the UIV matching the MSLV had a significantly lower prevalence of shoulder imbalance of 23% (odds ratio 4.08, 95% CI 1.22-13.7, P = 0.02). Setting the MSLV as the UIV in PSF for AIS Lenke type 2 may reduce the prevalence of postoperative shoulder imbalance.

A case of adult-onset Grisel's syndrome.

Aim: Grisel's syndrome is a non-traumatic subluxation of the atlanto-axial joint that occurs after infection or inflammation in the otolaryngological area, primarily in children.Method: This report describes the clinical characteristics of an extremely rare case of adult-onset Grisel's syndrome.Result: A 77-year-old woman presented with neck and bilateral shoulder pain and stiffness. Her temperature was 37.6 °C. Blood testing revealed a mildly elevated inflammatory response, although blood cultures were negative. Computed tomography (CT) showed atlanto-axial subluxation and joint destruction. T2-weighted magnetic resonance imaging (MRI) displayed high signals in the soft tissues in the anterior space of the atlas and axis, posterior wall of the pharynx, and interspinous ligament, indicating spinal cord compression at the C1 level. Differential diagnoses of inflammation and diseases causing atlanto-axial subluxation included rheumatoid arthritis, amyloidosis, pyogenic spondylitis due to posterior pharyngeal abscess, and crowned dens syndrome. After the systematic elimination of each condition, we considered Grisel's syndrome and began non-surgical treatment with intravenous antibiotics and a Philadelphia neck collar. Her inflammatory response and neck pain gradually decreased. Six months later, there was no progression of instability. She was able to walk unaided and live normally with the use of a neck collar as needed.Conclusion: Grisel's syndrome occurs predominantly in children, but can also afflict adults. Since early diagnosis and treatment can improve symptoms in some cases and prevent progressive atlanto-axial instability, prompt evaluation of the atlanto-axial joint using CT or MRI is advised in patients with neck pain and limited range of motion.

Tarsal Tunnel Syndrome Caused by a Schwannoma of the Posterior Tibial Nerve.

Schwannoma is the most common tumor of the peripheral nerve sheath. However, there have been few reports on schwannoma of the posterior tibial nerve causing tarsal tunnel syndrome. We report on a 60-year-old man with tarsal tunnel syndrome caused by a schwannoma of the posterior tibial nerve, which was first diagnosed as a ganglion cyst. After enucleation of this tumor, the patient was asymptomatic and had no related sequelae except for minor numbness in the plantar aspects of his digits. Although schwannoma of the posterior tibial nerve is rare, it should be considered even if a ganglion is clinically suspected.

Successful Closed Reduction of a Lateral Elbow Dislocation.

In this report, we present a case of lateral elbow dislocation treated with closed reduction. Lateral elbow dislocation is rare, and a closed reduction is reported with even less frequency. The reduction can be hindered by swelling and soft tissue interposition, and we describe the use of a nonoperative reduction technique performed under mild sedation with early physiotherapy to avoid joint stiffness. No additional complication was observed, and the normal range of elbow movement and function was obtained by early physiotherapy.