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.

Impact of landmark crater creation on improving accuracy of pedicle screw insertion in robot-assisted scoliosis surgery.

PURPOSE: This study evaluated the impact of the Landmark Crater (LC) method on pedicle perforation rates in robot-guided surgery for pediatric scoliosis for each pedicle diameter. METHODS: Seventy-six scoliosis patients underwent robot-assisted posterior spinal fusion. The cohort consisted of 19 male and 57 female patients, with a mean ± standard deviation age of 17.5 ± 7.7 years and a preoperative Cobb angle of 57.0 ± 18.5°. The LC method is a method in which craters that serves as a landmark are created in advance at the planned PS insertion site of all pedicles within the intraoperative CT imaging area. The patients were divided into the LC group, in which PS insertion was performed using the LC method, and the control group using the conventional PS insertion method. Overall and pedicle perforation rates for each pedicle outer diameter were compared between the groups by Fisher's exact test. RESULTS: The LC group exhibited a significantly lower pedicle major perforation rate than did the control group (2.7% vs. 6.2%, P = 0.001). The perforation rates in pedicles with a pedicle outer diameter > 6 mm, 4-6 mm, 2-4 mm, and < 2 mm were 0.61%, 1.6%, 5.1%, and 21%, in the LC group and 0.75%, 4.1%, 12%, and 50% in the control group, respectively. CONCLUSION: In robot-assisted surgery for pediatric scoliosis, the LC method enabled significantly lower pedicle perforation rates over the conventional method. Both the LC and conventional methods exhibited higher perforation rates for smaller pedicle diameters.

Excessive posterior placement of upper instrumented vertebra relative to lower instrumented vertebra as a predictor of proximal junction kyphosis after selective spinal fusion for adolescent idiopathic scoliosis Lenke type 5C curves.

PURPOSE: We defined sagittal S-line tilt (SSLT) as the tilt of the line connecting the upper instrumented vertebra and the lower instrumented vertebra. This study aimed to: (1) examine the correlation between SSLT and proximal junctional angle (PJA) change values, and (2) determine the cut-off value of SSLT with respect to proximal junctional kyphosis (PJK) occurrence. METHODS: Eighty-six consecutive patients (81 female and 5 male; mean age: 15.8 years) with Lenke 5C AIS who underwent posterior selective spinal fusion. Pearson's correlation coefficients were used to examine the relationship between preoperative SSLT and changes in PJA from preoperative to 2 years postoperative. The impact of SSLT on PJK at 2 years after surgery was assessed using a receiver operating characteristic (ROC) curve. RESULTS: We observed a moderate positive correlation between preoperative SSLT and change in PJA (R = 0.541, P < 0.001). We identified 18 patients (21%) with PJK at 2 years postoperative. Mean preoperative SSLT in the PJK group and the non-PJK group differed significantly at 23.3 ± 4.1° and 16.1 ± 5.0°, respectively (P < 0.001). The cut-off value of preoperative SSLT for PJK at 2 years postoperative was 18° in ROC curve analysis, with a sensitivity of 94%, specificity of 68%, and area under the ROC curve of 0.868. CONCLUSION: In selective lumbar fusion for AIS Lenke type 5C curves, preoperative SSLT was significantly correlated with PJA change from preoperative to 2 years postoperative. SSLT was a predictor of PJK occurrence, with a cut-off value of 18°.

Usefulness of modified S-line for upper instrumented vertebra selection in adolescent idiopathic scoliosis Lenke type 1C curve.

PURPOSE: Determine the effect of using the modified S-line vertebra (MSLV) as the upper instrumented vertebra (UIV) on postoperative trunk balance, L4 tilt, and clinical outcomes in selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS) Lenke type 1C curve. METHODS: Twenty-eight consecutive patients (all female; mean age: 15.4±2.0 years) with AIS Lenke type 1C curve were retrospectively enrolled. Primary outcome measures were coronal balance (absolute distance between C7 and the center of the sacral vertical line), L4 tilt, and Scoliosis Research Society (SRS)-22r scores at 2 years postoperatively. The group with the MSLV at the UIV was designated as the MSLV group (18 patients), and the group with the MSLV proximal (12 patients) or distal (4 patients) to the UIV was defined as the non-MSLV group. RESULTS: We observed no significant differences between the groups regarding age, LIV and stable vertebra positioning, or preoperative X-ray parameters. Postoperative coronal balance was significantly better in the MSLV group (0.39±0.08 vs. 1.34±0.22 cm; P.

Frequency and Associated Factors of Venous Thromboembolism in Cervical Spine Surgery.

BACKGROUND: Venous thromboembolism (VTE) is a well-known complication after spine surgery. As many cases of cervical spine disease result in severe gait disturbance due to myelopathy, it may harbor a higher risk of VTE than other spinal disorders. However, few studies have focused primarily on cervical spine surgery to date. This investigation sought to determine the prevalence of VTE after cervical spine surgery and identify patient-based risk factors. METHODS: The medical data of 341 consecutive patients (240 men and 101 women; mean age, 68.1 years) who underwent cervical spine surgery were retrospectively examined. Logistic regression models were employed to examine the prevalence, characteristics, and risk factors of postoperative VTE. RESULTS: In this study, 2.6% of cervical spine surgery patients experienced postoperative VTE. In comparisons of VTE and non-VTE groups, significant differences were found for age (79.6 years vs 67.7 years, P < 0.01), 1-week postoperative D-dimer level (10.6 µg/mL vs 2.7 µg/mL, P < 0.01), and cardiovascular disease (44.4% vs 11.1%, P = 0.011). Multivariate analysis identified elevated postoperative D-dimer level and cardiovascular disease as significantly associated with postsurgical VTE with respective odds ratios of 1.54 and 9.52. CONCLUSION: Postoperative VTE in cervical spine surgery was seen in 2.6% of cases. Patients with elevated postoperative D-dimer level and cardiovascular disease may be at increased risk of VTE and may require additional observation. CLINICAL RELEVANCE: Spine surgeons should take into account that patients with elevated postoperative D-dimer levels and cardiovascular disease may be at increased risk for VTE.

A case of spinal myoclonus in a patient with elective cesarean section.

BACKGROUND: Transient myoclonic involuntary movements, typically referred to as spinal myoclonus (SM), rarely develop in the extremities following neuraxial anesthesia (NA). NA indications in patients with history of SM following NA (SM-NA) are unknown. CASE PRESENTATION: A 33-year-old woman developed SM-NA after elective cesarean section (CS). Approximately 130 min after spinal anesthesia induction, she began exhibiting involuntary movements, which became most severe after approximately 3 h. The involuntary movements gradually decreased without treatments and disappeared after approximately 5 h. The patient underwent CS on three occasions. The first CS (age, 29 years) was under a combination of spinal and epidural anesthesia. The third CS (age, 35 years) was completed using only spinal anesthesia. There were no neurological events during the postoperative courses for the first and third CS. CONCLUSIONS: SM-NA can unexpectedly occur, and history of SM-NA may not be contraindicative for repeated NA.