A prospective clinical study of a multistep screw insertion method using a patient-specific screw guide template system (SGTS) for the cervical and thoracic spine.
To evaluate the efficacy of SGTS ...for inserting screws into the cervical and thoracic spine.
Posterior screw fixation is a standard procedure for spinal instrumentation; however, screw insertion carries the risk of injury to neuronal and vascular structures.
Preoperative bone images of the computed tomography (CT) scans were analyzed using 3D/multiplanar imaging software, and the screw trajectories were planned. Plastic templates with screw-guiding structures were created for each lamina using 3D design and printing technology. Three types of templates were made for precise multistep guidance, and all the templates were specially designed to fit and lock onto the lamina during the procedure. In addition, plastic vertebra models were generated, and preoperative screw insertion simulation was performed. This patient-specific SGTS was used to perform the surgery, and CT scanning was used to postoperatively evaluate screw placement.
Enrolled to verify this procedure were 103 patients with cervical, thoracic, or cervicothoracic pathologies. The SGTS were used to place 813 screws. Preoperatively, each template was found to fit exactly and to lock onto the lamina of the vertebra models. In addition, intraoperatively, the templates fit and locked onto the patient lamina, and the screws were inserted successfully. Postoperative CT scans confirmed that 801 screws (98.5%) were accurately placed without cortical violation. There were no injuries to the vessels or nerves.
The multistep, patient-specific SGTS is useful for intraoperative pedicle screw (PS) navigation in the cervical and thoracic spine. This method improves the accuracy of PS insertion and reduces the operating time and radiation exposure during spinal fixation surgery.
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Purpose
It has been reported that the incidence of post-operative segmental nerve palsy, such as C5 palsy, is higher in posterior reconstruction surgery than in conventional laminoplasty. Correction ...of kyphosis may be related to such a complication. The aim of this study was to elucidate the risk factors of the incidence of post-operative C5 palsy, and the critical range of sagittal realignment in posterior instrumentation surgery.
Methods
Eighty-eight patients (mean age 64.0 years) were involved. The types of the disease were; 33 spondylosis with kyphosis, 27 rheumatoid arthritis, 17 athetoid cerebral palsy and 11 others. The patients were divided into two groups; Group P: patients with post-operative C5 palsy, and Group NP: patients without C5 palsy. The correction angle of kyphosis, and pre-operative diameter of C4/5 foramen on CT were evaluated between the two groups. Multivariate logistic regression analysis was used to determine the critical range of realignment and the risk factors affecting the incidence of post-operative C5 palsy.
Results
Seventeen (19.3 %) of the 88 patients developed C5 palsy. The correction angle of kyphosis in Group P (15.7°) was significantly larger than that in Group NP (4.5°). In Group P, pre-operative diameters of intervertebral foramen at C4/5 (3.2 mm) were significantly smaller than those in Group NP (4.1 mm). The multivariate analysis demonstrated that the risk factors were the correction angle and pre-operative diameter of the C4/5 intervertebral foramen. The logistic regression model showed a correction angle exceeding 20° was critical for developing the palsy when C4/5 foraminal diameter reaches 4.1 mm, and there is a higher risk when the C4/5 foraminal diameter is less than 2.7 mm regardless of any correction.
Conclusions
This study has indicated the risk factors of post-operative C5 palsy and the critical range of realignment of the cervical spine after posterior instrumented surgery.
Purpose
The surgical strategy for cervical spondylotic myelopathy (CSM) accompanying local kyphosis is controversial. The purpose of the present study was to compare and evaluate the outcomes of two ...types of surgery for CSM accompanying local kyphosis: (1) laminoplasty alone (LP) and (2) posterior reconstruction surgery (PR) in which we corrected the local kyphosis using a pedicle screw or lateral mass screw.
Methods
Sixty patients who presented with local kyphosis exceeding 5° were enrolled. LP and PR were each performed on a group of 30 of these patients; 30 CSM patients without local kyphosis, who had undergone LP, were used as controls. The follow-up period was 2 years or longer. Preoperative local kyphosis angles in LP and PR were 8.3° ± 4.4° and 8.8° ± 5.7°, respectively. Preoperative C2–7 angles in LP, PR and controls were −1.7° ± 9.6°, −0.4° ± 7.2° and −12.0° ± 5.6°, respectively. The recovery rate of the JOA score, local kyphosis angle and C2–7 angle at post-op and follow-up were compared between the groups.
Results
The recovery rate of the JOA score in the LP group (32.6 %) was significantly worse than that in the PR group (44.5 %) and that of controls (53.8 %). Local kyphosis angles in the PR and LP groups at follow-up were 4.0° ± 8.6° and 8.0° ± 6.0°, respectively. However, although the C2–7 angle at follow-up was improved to −11.1° ± 12.7° in PR, and maintained at −11.6° ± 6.2° in controls, it deteriorated to 0.5° ± 12.7° in LP.
Conclusions
The present study is the first to compare the outcomes between LP alone and PR for CSM accompanying local kyphosis. It revealed that PR resulted in a better clinical outcome than did LP alone. This result may be due to reduction of local kyphosis, stabilization of the unstable segment, and/or the maintenance of C2–7 angle until follow-up in the PR group.
Retrospective clinical analyses of patients with cervical spondylotic amyotrophy (CSA).
To report the clinical outcomes and predictive factors relating to the prognosis in conservative and surgical ...treatments for CSA.
CSA is a clinical entity characterized by muscle atrophy in the upper extremity without marked sensory disturbance or spastic tetraparesis. The indications for, and outcomes of conservative and surgical treatments for CSA have not been clearly enunciated.
Ninety patients with CSA were enrolled in this study. All of them initially received continuous cervical traction for 2 to 3 weeks as inpatients. If this conservative treatment was ineffective, surgical intervention was carried out after informed consent was obtained. We investigated the outcome of conservative treatment, the predictive factors relating to the prognosis of the conservative treatment, and the outcome of surgery after initial conservative treatment failed.
After initial conservative treatment, 42 patients (46.7%) showed excellent or good outcome, 29 patients underwent surgery, and 19 patients declined surgery. Consequently, 61 patients were conservatively followed up. At final follow-up, 40% of the patients still showed excellent or good neurologic status by conservative treatment, and this group was characterized by age <50 years, duration of symptoms <6 months, single-level stenosis, foraminal stenosis, and a good response to traction therapy. Additional 5 patients underwent surgery during follow-up because of deterioration of symptom, and 34 patients consequently underwent surgery at the final follow-up. Of 34, 28 (82%) patients who underwent surgery obtained neurologic improvement.
The present study has demonstrated the outcome of conservative and of surgical treatments for CSA, together with the predictive factors relating to the prognosis. Conservative treatment should be initially tried on CSA patients, especially those with predictive factors relating to a better prognosis. However, if conservative treatment failed, surgical intervention was successful.
A prospective comparative study about the incidence of postoperative C5 palsy and multivariate analysis of the risk factors of C5 palsy.
To clarify the risk factors of occurrence of C5 palsy after ...laminoplasty (LP) by comparing the 2 surgical procedures of open-door and double-door LP prospectively.
The incidence of C5 palsy has been reported to average 4.6%, and there has been no difference of the incidence among surgical procedures. However, there were only indirect retrospective studies.
A total of 146 patients who underwent the LP procedure between 2006 and 2007 were studied prospectively. In 2006, the patients were assigned to undergo the open-door LP, and in 2007, they were assigned to undergo the double-door LP. The incidence of postoperative C5 palsy was compared prospectively between these 2 LP procedures, and the risk factors of C5 palsy were detected with multivariate logistic regression analysis.
Postoperative C5 palsy occurred in 7 of 73 cases after open-door LP (9.6%) and in 1 of 73 cases after double-door LP (1.4%). The incidence of C5 palsy after open-door LP was statistically higher than the one after double-door LP (P = 0.029), and open-door LP was recognized as a significant risk factor for postoperative C5 paralysis (odds ratio: 69.6, P = 0.043). In addition, ossification of posterior longitudinal ligament (OPLL) was recognized as a significant risk factor for postoperative C5 paralysis (odds ratio: 43.8, P = 0.048).
This study showed significant evidence indicating the higher risk of postoperative C5 palsy in open-door LP than double-door LP. Because OPLL as well as open-door LP were recognized as the risk factors of C5 palsy, asymmetric decompression by open-door LP might introduce imbalanced rotational movement of spinal cord and result in C5 palsy. We recommend double-door LP to minimize the postoperative C5 palsy, in particularly, if the patient has OPLL.
Cervical spondylotic myelopathy (CSM) is a degenerative disease and occurs more frequently with age. In fact, the development of non-herniated CSM under age 30 is uncommon. Therefore, a retrospective ...case series was designed to clarify clinical and radiological characteristics of young adult patients with CSM under age 30.
A total of seven patients, all men, with non-herniated, degenerative CSM under age 30 were retrieved from the medical records of 2598 hospitalized CSM patients (0.27%). Patient demographics and backgrounds were assessed. The sagittal alignment, congenital canal stenosis, dynamic canal stenosis, and vertebral slips in the cervical spine were radiographically evaluated. The presence of degenerative discs, intramedullary high-signal intensity lesions, and sagittal spinal cord compression on T2-weighted magnetic resonance images (MRIs) and axial spinal cord deformity on T1-weighted MRIs was identified.
All patients (100.0%) had relatively high daily sports activities and/or jobs requiring frequent neck extension. Cervical spine radiographs revealed the sagittal alignment as the "reverse-sigmoid" type in 57.1% of patients and "straight" type in 28.6%. All patients (100.0%) presented congenital cervical stenosis with the canal diameter ≤12 mm and/or Torg-Pavlov ratio <0.80. Furthermore, all patients (100.0%) developed dynamic stenosis with the canal diameter ≤12 mm and/or posterior vertebral slip ≥2 mm at the neurologically responsible segment in full-extension position. In MRI examination, all discs at the neurologically responsible level (100.0%) were degenerative. Intramedullary abnormal intensity lesions were detected in 85.7% of patients, which were all at the neurologically responsible disc level.
Patients with non-herniated, degenerative CSM under age 30 are rare but more common in men with mild sagittal "reverse-sigmoid" or "straight" deformity and congenital canal stenosis. Relatively high daily activities, accumulating neck stress, can cause an early development of intervertebral disc degeneration and dynamic canal stenosis, leading to CSM in young adults.
A prospective minimum 5-year follow-up study of the cervical spine in patients with rheumatoid arthritis (RA) initially without cervical involvement.
To clarify the incidence and aggravation of ...cervical spine instabilities and their predictive risk factors in patients with RA.
Many reports have shown the progression of cervical spine involvement in RA. However, few articles have described comprehensive evaluation of its prognostic factors.
A total of 140 patients with "definite" or "classical" RA initially without cervical involvement were prospectively followed for more than 5 years. Radiographical cervical findings were classified into 3 instabilities: atlantoaxial subluxation (AAS: atlantodental interval >3 mm), vertical subluxation (VS: Ranawat value <13 mm), and subaxial subluxation (SAS: irreducible translation ≥ 2 mm). "Severe" extents were defined as AAS with atlantodental interval 10 mm or more, VS with Ranawat value 10 mm or less, and SAS with translation 4 mm or more or at multiple levels. Incidence of these developments and predictors for "severe" instabilities were investigated.
During 6.0 ± 0.5 years, 43.6% of 140 patients developed cervical instabilities: AAS in 32.1%, VS in 11.4%, and SAS in 16.4% with some combinations. "Severe" instabilities were exhibited in 12.9% of patients: AAS in 3.6%, VS in 6.4%, and SAS in 5.0%. Furthermore, 4.3% presented canal stenosis, with 13 mm or less space available for the spinal cord (SAC) due to "severe" AAS or "severe" VS in 2.9% and 12 mm or less SAC due to "severe" SAS in 2.1%. Multivariable logistic regression analysis identified corticosteroid administration, mutilating changes at baseline, and the development of nonmutilating into mutilating changes during the follow-up period correlated with "severe" instabilities (P < 0.05).
A minimum 5-year follow-up reveals the occurrence of cervical instabilities in 43.6%, "severe" aggravation in 12.9%, and decreased SAC in 4.3% of patients with RA. Characteristics of severe disease activity-established mutilating changes, progressive development into mutilating changes, and potentially concomitant corticosteroid treatment-are indicators for poor prognosis of the cervical spine in RA.
To clarify the incidence and predictive risk factors of cervical spine instabilities which may induce compression myelopathy in patients with rheumatoid arthritis (RA).
Three types of cervical spine ...instability were radiographically categorized into "moderate" and "severe" based on atlantoaxial subluxation (AAS: atlantodental interval >3 mm versus ≥10 mm), vertical subluxation (VS: Ranawat value <13 mm versus ≤10 mm), and subaxial subluxation (SAS: irreducible translation ≥2 mm versus ≥4 mm or at multiple). 228 "definite" or "classical" RA patients (140 without instability and 88 with "moderate" instability) were prospectively followed for >5 years. The endpoint incidence of "severe" instabilities and predictors for "severe" instability were determined.
Patients with baseline "moderate" instability, including all sub-groups (AAS(+) VS(-) SAS(-), VS(+) SAS(-) AAS(±), and SAS(+) AAS(±) VS(±)), developed "severe" instabilities more frequently (33.3% with AAS(+), 75.0% with VS(+), and 42.9% with SAS(+)) than those initially without instability (12.9%; p<0.003, p<0.003, and p = 0.061, respectively). The incidence of cervical canal stenosis and/or basilar invagination was also higher in patients with initial instability (17.5% with AAS(+), 37.5% with VS(+), and 14.3% with SAS(+)) than in those without instability (7.1%; p = 0.028, p<0.003, and p = 0.427, respectively). Multivariable logistic regression analysis identified corticosteroid administration, Steinbrocker stage III or IV at baseline, mutilating changes at baseline, and the development of mutilans during the follow-up period correlated with the progression to "severe" instability (p<0.05).
This prospective cohort study demonstrates accelerated development of cervical spine involvement in RA patients with pre-existing instability--especially VS. Advanced peripheral erosiveness and concomitant corticosteroid treatment are indicators for poor prognosis of the cervical spine in RA.
Purpose To objectively assess elderly patients with carpal tunnel syndrome to characterize their preoperative severity and prognosis after carpal tunnel release using a electrophysiological severity ...scale. Methods Electrophysiologic assessment was performed preoperatively and 1 year postoperatively following carpal tunnel release in 112 hands in patients over 70 years of age prospectively by the use of the following electrophysiological severity scale: stage 1, normal distal motor latency (DML) and normal sensory conduction velocity (SCV); stage 2, DML ≥ 4.5 milliseconds and normal SCV; stage 3, DML ≥ 4.5 milliseconds and SCV < 40.0 m/s; stage 4, DML ≥ 4.5 milliseconds and non-measurable SCV; stage 5; non-measurable DML and non-measurable SCV. Additionally, the outcomes of clinical symptoms of pain, nocturnal symptoms, numbness, loss of 2-point discrimination in the median nerve territory, and thenar atrophy were assessed. Results The mean age of patients was 77 years at the time of the operation. Preoperatively, the most common severity was stage 5 (70 of 112 hands, 63%), and clustering stage 4 and 5 together as severe resulted in 103 hands (92%). One year postoperatively, 97 hands (87%) demonstrated at least one stage improvement, and the numbers of mild (stage 1 or 2) increased from 3 (3%) to 45 hands (40%). Parallel with the electrophysiological improvement, pain and nocturnal symptoms resolved in 17 of 17 hands and 11 of 11 hands, respectively, in whom they were present preoperatively. Numbness, loss of 2-point discrimination, and thenar atrophy demonstrated the improvement in 96 of 112 (86%) hands, in 58 of 112 (52%) hands, and in 80 of 96 (83%) hands. Conclusions We observed electrophysiologic improvement in 86% of elderly patients following carpal tunnel release. Electrophysiologic outcomes correlated with improvement in clinical variables. Type of study/level of evidence Therapeutic IV.
Internal fixation with intramedullary nails has gained popularity for the treatment of trochanteric femoral fractures, which are common injuries in older individuals. The most common complications ...are lag screws cut-out from the femoral head and femoral fracture at the distal tip of the nail. Herein, we report a rare complication of postoperative medial pelvic migration of the lag screw with no trauma. The patient was subsequently treated by lag screw removal via laparoscopy. This case suggests that optimal fracture reduction, adequate position of the lag screw, and careful attention to set screw insertion are important to prevent complications. Additionally, laparoscopic surgery might be able to remove the lag screw more safely than removal from the femoral side.
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