Journal of Spinal Disorders & Techniques最新文献

Study design: Retrospective cohort study.

Objective: To study clinical and radiologic outcomes after anterior cervical discectomy and fusion (ACDF) using a zero-profile anchored spacer compared with a standard interposition graft with anterior plating.

Summary of background data: Anterior plating increases fusion rates in ACDF but is associated with higher rates of postoperative dysphagia. Reduction of plate thickness or zero-profile fixation of the interposition graft have been suggested to decrease the incidence of postoperative dysphagia.

Methods: Retrospective cohort study of 70 consecutive patients of whom the first 35 patients underwent ACDF with anterior plating and the remaining patients received an LDR device. Patient demographics, operative details, neurological impairment, complications, and radiographic imaging were reviewed. Dysphagia occurring in the immediate postoperative period and lasting for >3 months was recorded.

Results: Both the zero-profile anchored spacer and a standard interposition graft with anterior plating resulted in improvement of neurological outcome at a mean follow-up time of 13.9 months. Fusion rates were found to be similar between ACDF with anterior plating (96.0%) and LDR (95.2%). Evaluation of postoperative radiographs revealed significantly more swelling of the prevertebral space (20.4±0.9 mm) after implantation of an anterior locking plate compared with a zero-profile device (15.6±0.7 mm, P<0.001). This difference remained significant at 6-month follow-up (P=0.035). Seven patients (20%) with ACDF and plating complained about swallowing difficulties beyond 3 months compared with only 1 patient with the LDR device (P=0.027). The severity of dysphagia was mild in all but 2 patients. Both patients with moderate and severe swallowing difficulties had undergone ACDF with anterior plating.

Conclusions: Zero-profile anchored spacers lead to similar clinical and radiographic outcomes compared with ACDF with plating and may carry a lower risk of postoperative dysphagia.

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has become a popular alternative to traditional methods of lumbar decompression and fusion. When compared with the open technique, the minimally invasive approach can result in decreased pain and blood loss as well as a shorter length of hospitalization. However, the narrower working channel through the tubular retractor increases the difficulty of decortication and bone grafting. Therefore, recombinant human bone morphogenetic proteins (rhBMP-2) is often utilized (although this is off-label) to create a more favorable interbody fusion environment. Recently, the use of rhBMP-2 has been associated with excessive bone growth in an MIS-TLIF. If this bone growth compresses the neighboring neural structures, patients may present with either new or recurrent radicular pain. Computed tomographic (CT) imaging can demonstrate heterotopic bone growth extending from the disk space into either the ipsilateral neuroforamen or lateral recess, which may result in the compression of the exiting or traversing root, respectively. The purpose of this article and the accompanying video is to demonstrate a technique for defining and resecting rhBMP-2-induced heterotopic bone growth following a previous MIS-TLIF.

Study design: A retrospective study of 58 patients undergoing cantilever transforaminal lumbar interbody fusion (c-TLIF).

Objectives: To evaluate morphologic changes in the intervertebral foramen (IVF) on the side contralateral to spacer insertion in patients undergoing c-TLIF using plain x-ray films and computed tomography scan.

Summary of background data: The morphologic changes in the contralateral lumbar foramen in c-TLIF using unilateral insertion of spacers have not been well studied.

Materials and methods: Fifty-eight consecutive patients with lumbar dysplastic changes or degenerative disk diseases underwent c-TLIF using 96 kidney-type spacers with local bone grafts. Radiographic findings (sagittal disk angle), computed tomography scan findings (coronal disk angle, disk height, foraminal height (FH), foraminal width, and cross-sectional area of IVF in contralateral lumbar foramen) were compared between preoperative period and 6 months after surgery. The correlations between contralateral lumbar foraminal dimensions and disk height, sagittal disk angle, and coronal disk angle were analyzed.

Results: After c-TLIF, sagittal angle, disk height, FH, foraminal width, and cross-sectional area of the IVF were significantly increased. Increase in posterior disk height showed a positive correlation with increases in FH, foraminal width, and cross-sectional area of IVF (r=0.235-0.511). However, the increase in sagittal disk angle showed a negative correlation with changes in foraminal width and cross-sectional area of IVF (r=-0.256 to -0.206).

Conclusions: Lumbar foraminal dimensions on the side contralateral to spacer insertion increased significantly after c-TLIF, suggesting that c-TLIF enables indirect decompression of the contralateral nerve root. Although increase in posterior disk height was shown to be an important factor to increase contralateral foraminal size, segmental lordosis was a risk factor for a decrease in contralateral foraminal size.

Study design: A retrospective study.

Objective: To identify significant kinematic changes in the cervical spine after cervical artificial disk replacement (ADR) using prostheses with diverse designs.

Summary of background data: Various types of artificial disks are used for cervical ADR. However, few clinical studies with a follow-up of 2 or more years have reported on the change in the curvatures and range of motion (ROM) of the cervical spine after cervical ADR in relation to different designs.

Methods: The cohort comprised 58 patients who underwent single-level cervical ADR for radiculopathy. The patients were divided into 4 groups according to the device they received: Mobi-C, Bryan, PCM, and Prestige LP. The radiographs of the cervical spine were obtained preoperatively and at 12, 24, and 36 months after surgery. Several kinematic parameters, including lordotic angles and ROM of the cervical spine, index level, and superior and inferior adjacent disk levels, were assessed preoperatively and at predefined follow-up time points.

Results: Cervical sagittal lordosis in patients who received Bryan and PCM prostheses increased at the last follow-up period. The 4 patient groups showed a trend toward an increase of lordosis in the superior adjacent segment with time. The patients who received the Bryan device lost their preoperative lordotic angle at the inferior adjacent level. The ROM of the cervical spine in patients who received Bryan and PCM prostheses increased at the last follow-up compared with preoperative values. The incidence of adjacent segment degeneration in the Mobi-C, Bryan, Prestige LP, and PCM groups were 14.2%, 25%, 9.0%, and 7.6%, respectively.

Conclusions: These results suggest preservation of sagittal ROM and increased superior adjacent segment kinematics, regardless of prosthesis design. Devices with an unconstrained design may not be beneficial to adjacent segment kinematics compared with semiconstrained prostheses.

Study design: Retrospective cohort study.

Objective: To investigate the relationship between cervical spine (C-spine) and rotator cuff (RTC) pathology.

Summary of background data: Cervical spine and RTC pathology cause significant shoulder pain in isolation and in tandem, but there is limited information about the relationship between these 2 entities.

Methods: Patients with a diagnosis of C-spine and/or RTC pathology between 2005 and 2011 were identified using a large national database composed of private payer as well as Medicare patient records. Patients with concomitant C-spine and RTC diagnoses were then stratified by age group and sex. Patients with lumbar spine (L-spine) and RTC pathology were used as a comparative group, and multivariate logistic regression was used for statistical analysis.

Results: Concomitant C-spine and RTC diagnoses were identified in 86,928 patients representing 13% of 679,112 patients with a RTC diagnosis and 16% of 531,177 patients with a C-spine diagnosis. The association between C-spine and RTC pathology increased significantly with age as RTC diagnoses were present in 13% of patients with C-spine pathology younger than 60 years old but increased to 25% in C-spine patients older than 60 years (P<0.0001). For patients over 60 years old who developed a new C-spine diagnosis, 11% would develop a new RTC diagnosis or undergo an operation for a RTC disorder within 5 years. Lumbar diagnosis codes (2,297,480 patients) were over 4 times more common than C-spine codes but RTC pathology had a significantly higher correlation with C-spine pathology than L-spine pathology (odds ratio, 2.32) and patients with C-spine pathology were more likely to develop new rotator cuff pathology (odds ratio, 1.53).

Conclusions: The association between cervical spine and RTC pathology is significantly greater than that between L-spine and RTC pathology and increases substantially with patient age. Further studies are needed to elucidate the cause of this relationship.

Study design: A prospective cohort study.

Objective: The purpose of this study was to determine whether the modified procedure reduces long-term axial symptoms (AS) and to understand better why the AS occur.

Summary of background data: Following Kurokawa's double-door laminoplasty, postoperative AS reduce the quality of life of patients with cervical spondylotic myelopathy. The etiology of AS remains unclear. Some studies report that preservation of the C7 spinous process can reduce the frequency of AS. The modified Kurokawa procedure prevents AS by preserving the semispinalis cervicis insertion in the spinous process of C2. However, it remains unclear whether the modified procedure lowers the incidence of AS in the long term (ie, >3 y).

Materials and methods: This prospective cohort study investigated preoperative and postoperative v, cervical intervertebral range of motion, postoperative neurological recovery, neck disability index, visual analog scale, surgical cost, and time and blood loss.

Results: Both groups had satisfied improvement of neurological functions (P>0.05). At 3 months and 1 year after surgery, the difference in frequency between no symptoms and mild/severe symptoms was significant (traditional group, 39.06%; modified group, 20.45%) (P<0.05). Interestingly, 3 years after surgery, there were no significant between-group differences (P>0.05).

Conclusions: This modified approach reduced the incidence of postoperative ASs at 3 months and 1 year after the operation; however, the between-group difference was not significantly different at the 3-year follow-up. The reason for this finding is unclear; it may indicate that the incidence of AS is caused by other factors, such as the preservation of the C7 spinous process rather than the C2 spinous process.

Study design: Retrospective case series.

Summary of background data: Large national inpatient databases estimate that approximately 200,000 lumbar fusions are performed annually in the United States alone. It is common for surgeons to routinely order postoperative hematologic studies to rule out postoperative anemia despite a paucity of data to support routine laboratory utilization.

Objective: To describe quantitative criteria to guide postoperative utilization of hematologic laboratory assessments.

Methods: A retrospective analysis of 490 consecutive lumbar fusion procedures performed at a single institution by 3 spine surgeons was performed. Inclusion criteria included instrumented and noninstrumented lumbar fusions performed for any etiology. Data were acquired on preoperative and postoperative hematocrit, platelets, and international normalized ratio as well as age, sex, number of levels undergoing operation, indication for surgery, and intraoperative blood loss. Multivariate logistic regression was performed to determine correlation to postoperative transfusion requirement.

Results: A total of 490 patients undergoing lumbar fusion were identified. Twenty-five patients (5.1%) required postoperative transfusion. No patients required readmission for anemia or transfusion. Multivariate logistic regression analysis demonstrated that reduced preoperative hematocrit and increased intraoperative blood loss were independent predictors of postoperative transfusion requirement. Intraoperative blood loss >1000 mL had an odds ratio of 8.9 (P=0.013), and preoperative hematocrit <35 had an odds ratio of 4.37 (P=0.008) of requiring a postoperative transfusion.

Conclusions: Routine postoperative hematologic studies are not necessary in many patients. High intraoperative blood loss and low preoperative hematocrit were independent predictors of postoperative blood transfusion. Our results describe quantitative preoperative and intraoperative criteria to guide data-driven utilization of postoperative hematologic studies following lumbar fusion.