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.

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.

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.

Ten-Year Results of Reconstruction for Rheumatoid Cervical Spine Lesions and Occurrence Factor of Subaxial Subluxation.

Study Design: Retrospective chart review. Purpose: This study evaluated long-term surgical outcomes of computer-assisted reconstruction using transarticular or cervical pedicle screws for cervical spine lesions caused by advanced rheumatoid arthritis (RA). Overview of Literature: We routinely employ C1-C2 transarticular and cervical pedicle screw instrumentation to reconstruct advanced and unstable RA cervical lesions. However, few reports are available on the long-term results of surgical reconstruction for rheumatoid cervical disorders, particularly regarding cervical pedicle screw fixation. Methods: Six subjects (all female) with RA cervical lesions who underwent atlantoaxial or occipitocervical fixation and were followed for at least 10 years were retrospectively studied. A frameless, stereotactic, optoelectronic, computed tomography-based image guidance system was used for correct screw placement. Variables including the Japanese Orthopaedic Association score, EuroQol, Ranawat value, and C2-C7 angle before and 2, 5, and 10 years after surgery were assessed along with the occurrence of subaxial subluxation (SAS). Results: Mean age at initial surgery was 58.2±7 years (range, 51-68 years), and mean follow-up period was 141±11 months (range, 122-153 months). Lesions included atlantoaxial subluxation (AAS, n=2) and AAS+vertical subluxation (n=4). Mean C2-C7 lordotic angle before and 2, 5, and 10 years after surgery was 20.1°±6.1°, 21.0°±4.0°, 18.8°±4.7°, and 17.8°±5.3°, respectively. SAS did not occur in cases maintaining the C2-C7 lordotic angle. In two cases where the C2-C7 lordotic angle declined from 5 years postoperatively, SAS occurred at the C2-C3 level in one and at the C4-C5 level in the other, both of which required reoperation. Conclusions: Patients with rheumatoid cervical lesions who undergo atlantoaxial or occipitocervical fixation using C1-C2 transarticular or pedicle screws carry a risk of SAS for up to 10 years postoperatively, which may require reoperation.