Variations in Practice among Asia-Pacific Surgeons and Recommendations for Managing Cervical Myelopathy: The First Asia-Pacific Spine Society Collaborative Study

Combined Anterior-Posterior Fusion Versus Posterior Alone Fusion for Cervical Myelopathy in Athetoid-Cerebral Palsy

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

Although some studies have discussed the use of lateral mass screws (LMSs) in patients with cerebral palsy (CP), it is unclear whether posterior LMS fixation alone is a suitable method. We aimed to compare the clinical, radiological, and surgical outcomes of 2 surgical modalities, namely, combined anterior-posterior (A-P) instrumented fusion and posterior fusion alone, in athetoid-type CP patients with cervical myelopathy (CM).

METHODS

We analyzed 63 patients with athetoid-CP and CM who underwent posterior fusion only with LMS (group A, 35 patients) and A-P fusion (group B, 28 patients). The primary outcome was the 1- and 3-year fusion rates for the surgical segments. The secondary outcomes included the clinical outcomes based on pain intensity determined using the visual analog scale score, neck disability index, and 17-point Japanese Orthopedic Association score, radiological, and surgical outcomes.

RESULTS

Fusion was achieved at 3 years postoperatively in 22 of 35 patients (63%) in group A and in 26 of 28 patients (93%) in group B (P = 0.02). The posterior neck pain intensity was also significantly lower in group B than in group A 2 and 3 years postoperatively (P = 0.02 and 0.01, respectively). The incidence of screw loosening and implant-related problems was higher in group A (60%) than in group B (21%) (P = 0.01). The other clinical and radiological parameters were similar between the groups.

CONCLUSIONS

For athetoid CP-induced CM, combined A-P fusion would result in superior clinical and radiological outcomes compared to posterior fusion alone.

Medial Pedicle Pivot Point Using Preoperative Computed Tomography Morphometric Measurements for Cervical Pedicle Screw Insertion: A Novel Technique and Case Series

This study describes a new and safe freehand cervical pedicle screw insertion technique using preoperative computed tomography (CT) morphometric measurements as a guide and a medial pedicle pivot point (MPPP) during the procedure. This study included 271 pedicles at 216 cervical spine levels (mean: 4.75 pedicles per patient). A pedicle diameter (PD) ≥ 3.5 mm was the cut-off for pedicle screw fixation. The presence and grade of perforation were detected using postoperative CT scans, where perforations were graded as follows: 0, no perforation; 1, perforation < 0.875 mm; 2, perforation 0.875-1.75 mm; and 3, perforation > 1.75 mm. The surgical technique involved the use of an MPPP, which was the point at which the lines representing the depth of the lateral mass and total length of the pedicle intersected, deep in the lateral mass. The overall success rate was 96.3% (261/271, Grade 0 or 1 perforations). In total, 54 perforations occurred, among which 44 (81.5%) were Grade 1 and 10 (18.5%) were Grade 2. The most common perforation direction was medial (39/54, 72.2%). The freehand technique for cervical pedicle screw fixation using the MPPP may allow for a safe and accurate procedure in patients with a PD ≥3.5 mm.

Subclinical gait disturbance and postoperative gait improvement in patients with degenerative cervical myelopathy

This study aimed to evaluate the subclinical gait abnormalities and the postoperative gait improvements in patients with degenerative cervical myelopathy using three-dimensional gait analysis. We reviewed the gait analysis of 62 patients who underwent surgical treatment for degenerative cervical myelopathy. The asymptomatic gait group included 30 patients and the gait disturbance group included 32 patients who can walk on their own slowly or need assistive device on stairs. The step width (17.2 cm vs. 15.9 cm, P = 0.003), stride length (105.2 cm vs. 109.1 cm, P = 0.015), and double-limb support duration (13.4% vs. 11.7%, P = 0.027) improved only in the asymptomatic gait group. Preoperatively, the asymptomatic gait group exhibited better maximum knee flexion angle (60.5° vs. 54.8°, P = 0.001) and ankle plantarflexion angle at push-off (− 12.2° vs. − 6.5°, P = 0.001) compared to the gait disturbance group. Postoperatively, maximum knee flexion angle (62.3° vs. 58.2°, P = 0.004) and ankle plantarflexion angle at push-off (− 12.8° vs. − 8.3°, P = 0.002) were still better in the asymptomatic gait group, although both parameters improved in the gait disturbance group (P = 0.005, 0.039, respectively). Kinematic parameters could improve in patients with gait disturbance. However, temporospatial parameters improvement may be expected when the operative treatment is performed before apparent gait disturbance.

Handgrip Strength Correlated with Falling Risk in Patients with Degenerative Cervical Myelopathy

Background: Few studies have investigated associations between hand grip strength (HGS) and the surgical outcomes of degenerative cervical myelopathy (DCM). Methods: This study was designed as a prospective observational study of 203 patients who had undergone fusion surgery for DCM. We divided the patients according to sex and HGS differences. Clinical outcome parameters, including HGS, a fall diary and four functional mobility tests (alternative step test, six-meter walk test, timed up and go test, and sit-to-stand test) were measured preoperatively, at 3 months and 1 year after surgery. Results: Mean patient ages were 59.93 years in the male group and 67.33 years in the female group (p = 0.000; independent t-test). The mean HGS of both hands improved significantly at postoperative 3 months and 1 year in all patients (p = 0.000 for both; ANOVA). In male patients, preoperative risk of falls was negatively correlated with HGS (p = 0.000). In female patients, pre- and postoperative risk of falls were correlated negatively with HGS (p = 0.000). The postoperative incidence of falls decreased in both groups (p = 0.000) Conclusions: Postoperative HGS in patients with DCM is correlated with postoperative falls and functional outcome differently, when comparing male and female patients, for predicting favorable outcomes and neurologic deficit recovery after surgery in DCM patients.

Surgical decision-making for ossification of the posterior longitudinal ligament versus other types of degenerative cervical myelopathy: anterior versus posterior approaches

Background

The debate between anterior or posterior approach for pathologies such as cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) have drawn heated debate but are still inconclusive.

Main body of the abstract

A narrative review was performed specifically to study the differences pertaining to OPLL and other causes of degenerative cervical myelopathy (DCM). Current evidence suggests that anterior approach is preferred for K-line (−) OPLL, K-line (+) with canal occupying ratio > 60% and DCM with pre-existing cervical kyphosis. Posterior approach is preferred for K-line (+) OPLL with canal-occupying ratio < 50–60%, and multi-level CSM. No particular advantage for either approach was observed for DCM in a lordotic cervical spine. Anterior approach is generally associated with more complications and thus needs to be weighed carefully during decision-making. The evidence is not convincing for comparing single versus multi-level involvement, and the role of patients' co-morbidity status, pre-existing osteoporosis and co-existent spinal pathologies in influencing patient outcome and surgical options. This should be a platform for future research directives.

Conclusion

From this review, evidence is still inconclusive but there are some factors to consider, and DCM and OPLL should be considered separately for decision-making. Anterior approach is considered for pre-existing cervical kyphosis in DCM, for K-line (−) regardless of canal-occupying ratio, and K-line (+) and canal-occupying ratio > 60% for OPLL patients. Posterior approach is considered for patients with multi-level pathology for DCM, and K-line (+) and canal-occupying ratio < 50–60% for OPLL.

Anterior cervical discectomy and fusion for cervical myelopathy using stand-alone tricortical iliac crest autograft: Predictive factors for neurological and fusion outcomes

PURPOSE

The purpose of this article is to investigate the outcomes after anterior cervical discectomy and fusion (ACDF) surgery with stand-alone tricortical iliac crest autograft and to determine predictive factors for poor neurological recovery, non-union, graft collapse and loss of C2-C7 sagittal alignment.

METHODS

This was a retrospective study involving patients with cervical myelopathy who underwent ACDF surgery with stand-alone tricortical iliac autograft between 2006 and 2016, with a minimum 2-year postoperative follow-up. Outcomes included the change in Japanese Orthopaedic Association (JOA) scores clinically and timing of fusion, graft height and C2-7 angle measured on lateral radiographs. Any complication such as neurological deterioration, non-union, graft collapse or loss of angle was recorded. Delayed union was considered as radiological union identified only beyond postoperative 6 months. Risk factors including age, smoking, drinking, comorbidities and operative levels were analysed through a multivariate regression for their respective influences on the various outcomes.

RESULTS

Of the 69 patients studied, none of the patients had non-union, while 33 (47.1%) achieved fusion in 6 months. The most common complications were anterior protrusion of graft (5.8%) and hoarseness (2.9%). The 1-year mean change in JOA score was 3.9 ± 2.7. The C2-7 angle gradually became more kyphotic, despite an initial lordosis correction intraoperatively. The graft height also gradually collapsed during subsequent follow-ups. Multivariate regression model suggested that diabetics (cumulative odds ratio 7.4) and drinkers (cumulative odds ratio 8.6) were associated with delayed union.

CONCLUSION

ACDF using tricortical iliac crest autograft has satisfactory outcomes with low occurrence of complications. Diabetics and drinkers were predictors of delayed union.