Anterior Surgical Technique Research Articles

Anterior surgical treatment for cervical degenerative radiculopathy: a prediction model for non-success

PurposeBy using data from the Norwegian Registry for Spine Surgery, we wanted to develop and validate prediction models for non-success in patients operated with anterior surgical techniques for cervical degenerative radiculopathy (CDR).MethodsThis is a multicentre longitudinal study of 2022 patients undergoing CDR surgery and followed for 12 months to find prognostic models for non-success in neck disability and arm pain using multivariable logistic regression analysis. Model performance was evaluated by area under the receiver operating characteristic curve (AUC) and a calibration test. Internal validation by bootstrapping re-sampling with 1000 repetitions was applied to correct for over-optimism. The clinical usefulness of the neck disability model was explored by developing a risk matrix for individual case examples.ResultsThirty-eight percent of patients experienced non-success in neck disability and 35% in arm pain. Loss to follow-up was 35% for both groups. Predictors for non-success in neck disability were high physical demands in work, low level of education, pending litigation, previous neck surgery, long duration of arm pain, medium-to-high baseline disability score and presence of anxiety/depression. AUC was 0.78 (95% CI, 0.75, 0.82). For the arm pain model, all predictors for non-success in neck disability, except for anxiety/depression, were found to be significant in addition to foreign mother tongue, smoking and medium-to-high baseline arm pain. AUC was 0.68 (95% CI, 0.64, 0.72).ConclusionThe neck disability model showed high discriminative performance, whereas the arm pain model was shown to be acceptable. Based upon the models, individualized risk estimates can be made and applied in shared decision-making with patients referred for surgical assessment.

Research protocol: Cervical Arthroplasty Cost Effectiveness Study (CACES): economic evaluation of anterior cervical discectomy with arthroplasty (ACDA) versus anterior cervical discectomy with fusion (ACDF) in the surgical treatment of cervical degenerative disc disease — a randomized controlled trial

IntroductionTo date, there is no consensus on which anterior surgical technique is more cost-effective in treating cervical degenerative disc disease (CDDD). The most commonly used surgical treatment for patients with single- or multi-level symptomatic CDDD is anterior cervical discectomy with fusion (ACDF). However, new complaints of radiculopathy and/or myelopathy commonly develop at adjacent levels, also known as clinical adjacent segment pathology (CASP). The extent to which kinematics, surgery-induced fusion, natural history, and progression of disease play a role in the development of CASP remains unclear. Anterior cervical discectomy with arthroplasty (ACDA) is another treatment option that is thought to reduce the incidence of CASP by preserving motion in the operated segment. While ACDA is often discouraged, as the implant costs are higher while the clinical outcomes are similar to ACDF, preventing CASP might be a reason for ACDA to be a more cost-effective technique in the long term.Methods and analysisIn this randomized controlled trial, patients will be randomized to receive ACDF or ACDA in a 1:1 ratio. Adult patients with single- or multi-level CDDD and symptoms of radiculopathy and/or myelopathy will be included. The primary outcome is cost-effectiveness and cost-utility of both techniques from a healthcare and societal perspective. Secondary objectives are the differences in clinical and radiological outcomes between the two techniques, as well as the qualitative process surrounding anterior decompression surgery. All outcomes will be measured at baseline and every 6 months until 4 years post-surgery.DiscussionHigh-quality evidence regarding the cost-effectiveness of both ACDA and ACDF is lacking; to date, there are no prospective trials from a societal perspective. Considering the aging of the population and the rising healthcare costs, there is an urgent need for a solid clinical cost-effectiveness trial addressing this question.Trial registrationClinicalTrials.gov NCT04623593. Registered on 29 September 2020.

Transnasal Endoscopic Approach for Osteoid Osteoma of the Odontoid Process in a Child: Technical Note and Systematic Review of the Literature.

Osteoid osteoma (OO) is a primary benign tumor that accounts for up to 3% of all bone tumors. The cervical spine is less affected by OOs, and very few cases of C2 OOs have been reported in the literature, both in adults and children. Surgery may be required in case of functional torticollis, stiffness, and reduced range of motion (ROM) due to cervical OOs refractory to medical therapy. Several posterior and anterior surgical techniques have been described to remove C2 OOs. In particular, anterior approaches to the cervical spine represent the most used surgical route for treating C2 OOs. We describe the first case of OO of the odontoid process removed through a transnasal endoscopic approach with the aid of neuronavigation in a 6-year-old child. No intraoperative complications occurred, and the post-operative course was uneventful. The patient had immediate relief of neck pain and remained pain-free throughout the follow-up period, with complete functional recovery of the neck range of motion (ROM). In this case, based on the favorable anatomy, the transnasal endoscopic approach represented a valuable strategy for the complete removal of an anterior C2 OO without the need for further vertebral fixation since the preservation of ligaments and paravertebral soft tissue.

Application of a new integrated low-profile anterior plate and cage system in single-level cervical spondylosis: a preliminary retrospective study

BackgroundAlthough ACDF has been widely used in treating cervical spondylosis and related diseases, the complications along with this anterior surgical technique have hindered its application and affected the postoperative outcome of the patients. Here, we investigated the clinical and radiological outcomes of a new integrated low-profile anterior plate and cage system for anterior cervical discectomy and fusion (ACDF) in treating cervical spondylosis.MethodsA total of 96 cervical spondylosis patients who underwent single-level ACDF between 2018 to 2020 in our institute were enrolled. There were 28 patients using the new implants and 68 patients using the zero-profile (Zero-P) implants. The Japanese Orthopedic Association (JOA) score and the visual analog scale (VAS) were used to evaluate the clinical outcomes. The cervical and segmental Cobb angle and range of motion (ROM) were used to assessed the radiological outcomes. Incidence of complications were also recorded. All data were recorded at pre-operation, 6-month and 12-month post-operation.ResultsAll patients were followed-up for at least 1-year, the mean follow-up time was over one year. The fusion rate was similar in the two groups. There was no significant difference in the postoperative JOA score recovery rate, postoperative VAS score of neck and arm pain, postoperative ROM, and incidence of complications between two groups (P > 0.05). However, postoperative cervical and segmental Cobb angle were better maintained in the new low-profile implant group compared to Zero-P group.ConclusionsThe clinical outcomes of the new low-profile implant were satisfactory and comparable to that of zero-profile system. It may have advantages in improving and maintaining the cervical lordosis, and can be an alternative device for single-level cervical spondylosis treated with ACDF.

LABIOMANDIBULAR GLOSSOTOMY APPROACH FOR CRANIOCERVICAL PATHOLOGIES - SPINE RECONSTRUCTION

ABSTRACT Objectives: Exposing the clivus and upper cervical spine should, ideally, provide an adequate surgical field in which the surgeon can safely decompress and stabilize the craniovertebral junction (CVJ). We present a series of four cases with a narrative review of the literature in which Median Labiomandibular Glossotomy was used to treat CVJ disorders, in order to highlight the importance and indications of this access. Methods: We performed a retrospective analysis of patients who underwent MLMG for several pathologies. The group comprised four patients (two men and two women). Five approaches were performed (one revision surgery). Results: The approach was suitable for all cases, clivus was achieved when necessary. Distally, C4 was exposed to obtain satisfactory osteosynthesis. Laterally, we had a good view of the tumor borders and control of the vertebral artery. Complications encountered were a superficial wound infection that was easily healed, a later pharyngeal wound dehiscence and pseudoarthrosis, all in the same patient. There are 3 main anterior surgical techniques for managing lesions of the clivus, foramen magnum or upper cervical vertebrae. We chose Median Labiomadibular Glossotomy (MLMG) as a primary option, which provided a direct view of the clivus, C3 – C4 caudally and a wider surgical field. The main advantages of the MLMG technique include direct access to spinal pathology, an avascular plane through the median pharyngeal raphe, and a wider surgical field in both the transverse and sagittal dimensions. Conclusion: This approach provides excellent exposure of the craniocervical junction and upper cervical spine. Level of evidence IV; Series of cases analyzed retrospectively.

Anterior Canal Reconstruction and Fusion for Myelopathy Caused by Degenerative Cervical Kyphosis and Stenosis With or Without Ossification of the Posterior Longitudinal Ligament.

This was a retrospective study. To introduce an anterior surgical technique for myelopathy caused by degenerative cervical kyphosis and stenosis (DCKS) with or without ossification of the posterior longitudinal ligament (OPLL). The optimal approach in the treatment of DCKS remains a controversy because each anterior or posterior route surgery has advantages and disadvantages. In the period from June 2017 through June 2019, a consecutive cohort of adults diagnosed with DCKS underwent anterior canal reconstruction and fusion (ACRF). All patients underwent x-ray, computed tomography, and magnetic resonance imaging of the cervical spine. Radiologic assessment included kyphosis, canal area, canal reconstruction, OPLL, and spinal cord curvature and morphology. The Japanese Orthopaedic Association (JOA) scoring system was used to evaluate the neurological status. Surgery-related and implant-related complications were all recorded. Follow-up was carried out at 3, 6, 12, 24, and 36 months postoperation. Fourty-one patients were included in the study, of which 19 presented with OPLL. Postoperatively, the canal area were significantly greater at last follow-up compared with preoperation (208.4 vs. 123.2 mm2; P=0.001). There was significant kyphosis correction (-17.6 vs. 8.5 degrees, P=0.001) at last follow-up. Ninety-six segmental canal reconstruction were performed, 89 (92.7%) reached bone fusion at both grooves with a mean time of 7.9 months. On sagittal magnetic resonance imaging, 33 (80.5%) patients presented with lordosis in the spinal cord curvature, 8 (19.5%) with straight. The mean JOA score at last follow-up was significantly better than preoperation (15.0 vs. 9.3 points; P<0.01). One patient presented with cerebrospinal fluid leakage, 1 with screw displacement and 2 with dysphagia. ACRF, receiving good correction of kyphosis, amplified canal area, solid instrumented fusion and circumferential decompression, is an effective and safe surgical technique for cervical myelopathy caused by DCKS with or without OPLL. Level III-a retrospective analysis.

Exclusion of Ossified Ligaments Behind C2 Vertebra Combined with Anterior Controllable Antedisplacement and Fusion for Cervical Ossification of the Posterior Longitudinal Ligament Extending to C2 Segment

We sought to introduce an anterior surgical technique for cervical ossification of posterior longitudinal ligament (OPLL) extending to C2. A total of 29 patients with multilevel OPLL extending to C2 underwent surgery from January 2016 to January 2019. The rationale of our surgical technique is to transect the ossified ligament at the level of C2/3, dividing OPLL into 2 parts. OPLL behind the C2 vertebra is reserved as "focus exclusion," and OPLL below C2 is performed anterior controllable antedisplacement and fusion. Neurologic condition was evaluated using the Japanese Orthopaedic Association scoring system and its improvement ratio. Radiologic assessment included type and extent of OPLL, occupying rate, thickness and length of ossified mass, and curvature of spinal cord. Surgery- and implant-related complications were recorded. The mean Japanese Orthopaedic Association score increased from 9.4 to 15.8 points at last follow-up, with a significant improvement (P < 0.01). The mean preoperative length of the ossified mass behind C2 was 15.4 mm, and its thickness was 2.2 mm, with no significant progression at last follow-up (15.3 mm and 2.2 mm, P > 0.05). There was also no statistical difference in OPLL thickness at the largest occupying rate level between preoperation and last follow-up (7.4 mm vs. 7.3 mm, P > 0.05). Four patients presented with cerebrospinal fluid leakage, 1 with screw displacement, and 1 with dysphagia. For patients with cervical OPLL extending to C2, exclusion of ossified ligaments behind C2 combined with anterior controllable antedisplacement and fusion below C2 is an effective and alternative technique.

Minimally invasive stabilization of thoracolumbar osteoporotic fractures

Minimally invasive stabilization of thoracolumbar osteoporotic fractures (OF) in neurologically intact patients is well established. Various posterior and anterior surgical techniques are available. The OF classification and OF score are helpful for defining the indications and choice of operative technique. This article gives an overview of the minimally invasive stabilization techniques, typical complications and outcome. Selective literature search and description of surgical techniques and outcome. Vertebral body augmentation alone can be indicated in painful but stable fractures of types OF1 and OF2 and to some extent for type OF3. Kyphoplasty has proven to be an effective and safe procedure with a favorable clinical outcome. Unstable fractures and kyphotic deformities (types OF3-5) should be percutaneously stabilized from posterior. The length of the pedicle screw construct depends on the extent of instability and deformity. Bone cement augmentation of the pedicle screws is indicated in severe osteoporosis but increases the complication rate. Restoration of stability of the anterior column can be achieved through additional vertebral body augmentation or rarely by anterior stabilization. Clinical and radiological short and mid-term results of the stabilization techniques are promising; however, the more invasive the surgery, the more complications occur. Minimally invasive stabilization techniques are safe and effective. The specific indications for the individual procedures are guided by the OF classification and the individual clinical situation of the patient.

A comparison of the perioperative outcomes of anterior surgical techniques for the treatment of multilevel degenerative cervical myelopathy.

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in adults. Multilevel ventral compressive pathology is routinely managed through anterior decompression and reconstruction, but there remains uncertainty regarding the relative safety and efficacy of multiple discectomies, multiple corpectomies, or hybrid corpectomy-discectomy. To that end, using a large national administrative healthcare data set, the authors sought to compare the perioperative outcomes of anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), and hybrid corpectomy-discectomy for multilevel DCM. Patients with a primary diagnosis of DCM who underwent an elective anterior cervical decompression and reconstruction operation over 3 cervical spinal segments were identified from the 2012-2017 National Surgical Quality Improvement Program database. Patients were separated into those undergoing 3-level discectomy, 2-level corpectomy, or a hybrid procedure (single-level corpectomy plus additional single-level discectomy). Outcomes included 30-day mortality, major complication, reoperation, and readmission, as well as operative duration, length of stay (LOS), and routine discharge home. Outcomes were compared between treatment groups by multivariable regression, adjusting for age and comorbidities (modified Frailty Index). Effect sizes were reported by adjusted odds ratio (aOR) or mean difference (aMD) and associated 95% confidence interval. The study cohort consisted of 1298 patients; of these, 713 underwent 3-level ACDF, 314 2-level ACCF, and 271 hybrid corpectomy-discectomy. There was no difference in 30-day mortality, reoperation, or readmission among the 3 procedures. However, on both univariate and adjusted analyses, compared to 3-level ACDF, 2-level ACCF was associated with significantly greater risk of major complication (aOR 2.82, p = 0.005), longer hospital LOS (aMD 0.8 days, p = 0.002), and less frequent discharge home (aOR 0.59, p = 0.046). In contrast, hybrid corpectomy-discectomy had comparable outcomes to 3-level ACDF but was associated with significantly shorter operative duration (aMD -16.9 minutes, p = 0.002). The authors found multiple discectomies and hybrid corpectomy-discectomy to have a comparable safety profile in treating multilevel DCM. In contrast, multiple corpectomies were associated with a higher complication rate, longer hospital LOS, and lower likelihood of being discharged directly home from the hospital, and may therefore be a higher-risk operation.

Anterior Surgical Techniques for Cervical Spondylotic Myelopathy: WFNS Spine Committee Recommendations.

ObjectiveThis study was performed to review the literature and to present the most up-to-date information and recommendations on the indications, complications, and success rate of anterior surgical techniques for cervical spondylotic myelopathy (CSM). The commonly performed anterior surgical procedures are multiple-level anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion and its variants (skip corpectomy and hybrid surgery), and oblique corpectomy without fusion. MethodsA comprehensive literature search and analysis were performed using MEDLINE (PubMed), the Cochrane Register of Controlled Trials, and the Web of Science for peer-reviewed articles published in English during the last 10 years. ResultsCorpectomy is mandated for ventral compression of fewer than 3 vertebral segments where single-level disc and osteophyte excision is inadequate to decompress the cord. Endoscopic or oblique partial corpectomy improves the sagittal canal diameter by 67% and obviates the need for an additional bone graft procedure. ConclusionThe indications of anterior surgery in patients with CSM include a straightened or kyphotic spine with a compression level lower than 3. With an appropriate choice of implants and meticulous surgical technique, surgical complications can be seen only rarely. Improvements after anterior surgery for CSM have been reported in 70% to 80% of patients.

Comparison of Three Anterior Techniques in the Surgical Treatment of Three-Level Cervical Spondylotic Myelopathy with Intramedullary T2-Weighted Increased Signal Intensity

To compare the clinical and radiologic outcomes of 3 anterior surgical techniques for the treatment of 3-level cervical spondylotic myelopathy (CSM) and the evolution of intramedullary T2-weighted increased signal intensity (ISI). A total of 98 consecutive patients (61 males, 37 females) with 3-level CSM who underwent anterior cervical surgery between January 2006 and January 2016 were retrospectively enrolled. Based on different anterior reconstructive techniques, the patients were divided into 3 groups: anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), and hybrid decompression and fusion (HDF) groups. The Japanese Orthopaedic Association score and its recovery rate were used to evaluate the clinical outcomes. The cervical alignment and range of motion were used to assess radiologic outcomes. In addition, the signal change ratio and length of ISI were used to measure the ISI. No statistical differences in preoperative factors were found among the 3 groups (P > 0.05). Although the HDF group had intermediate surgery time and blood loss compared with other groups (P < 0.05), it achieved greater postoperative Japanese Orthopaedic Association score and recovery rate than other groups (P < 0.05). The postoperative C2-C7 lordotic angle and postoperative range of motion in the HDF group were similar to that in the ACDF group (P > 0.05), both greater than that in the ACCF group (P < 0.05). The incidence of complications in the HDF group was close to the ACDF group (P > 0.05), and both groups were lower than that in the ACCF group (P < 0.05). In addition, the postoperative signal change ratio in the HDF group was lower than in other groups (P < 0.05). The postoperative length of ISI in the HDF group was similar to the ACCF group (P > 0.05), which was both shorter than that in the ACDF group (P < 0.05). For patients with 3-level CSM with ISI on T2-weighted MRI, HDF can be considered as the optimal technique that achieves better clinical and radiologic outcomes than the ACDF or ACCF procedure. HDF also has a better postoperative regression of ISI compared with the ACDF or ACCF procedure, which may potentially be an important indicator for improving surgical outcomes.

Cervical Spine Deformity-Part 2: Management Algorithm and Anterior Techniques.

A sound operative plan based on solid understanding of the pathology and biomechanics is the most important part of cervical deformity correction. Many different surgical options exist for operative management of cervical spine deformities. However, selecting the correct approach that ensures the optimal clinical outcome can be challenging and often controversial. In Part 2 of this three-part review series, we discuss the pre-operative planning, management algorithm, and anterior surgical techniques for cervical deformity correction.

Pulmonary function after less invasive anterior instrumentation and fusion for idiopathic thoracic scoliosis

PurposeStandard thoracotomy for anterior instrumentation and fusion of the thoracic spine in idiopathic scoliosis may have detrimental effects on pulmonary function. In this study we describe a less invasive anterior surgical technique and show the pre- and postoperative pulmonary function with a minimum follow-up of 2 years.MethodsTwenty patients with Lenke type 1 adolescent thoracic idiopathic scoliosis were treated with anterior spinal fusion and instrumentation. The mean preoperative Cobb angle of the thoracic curve was 53° ± 5.8. Pulmonary function tests (PFT) and radiographic evaluation was performed.ResultsThe mean postoperative correction in Cobb angle of the thoracic curve was 27° ± 8.2 (49%).The mean preoperative FEV1 was 2.81 ± 0.43 L, which increased to 3.14 ± 0.50 L at 2 years postoperatively (P = 0.000). The mean FEV1% did not change (89.60 ± 7.49% preoperatively, versus 90.53 ± 5.95% at 2 years follow-up, P = 0.467). The TLC increased from 4.62 ± 0.62 L preoperatively to 5.17 ± 0.63 L at 2 years follow-up (P = 0.000). The FEV1% at two years of follow-up improved to 104% of the FEV1% predicted value. The FEV1 improved to 97% of the FEV1 predicted value.ConclusionAnterior spinal fusion for idiopathic scoliosis by means of a minimal open thoracotomy proved to be a safe surgical technique that resulted in an improvement of pulmonary function. Our results are similar to those of thoracoscopic procedures reported in literature.

Cervical spine surgery: an historical perspective.

Continued innovation in surgery requires a knowledge and understanding of historical advances with a recognition of successes and failures. To identify these successes and failures, we selectively reviewed historical literature on cervical spine surgery with respect to the development of (1) surgical approaches, (2) management of degenerative disc disease, and (3) methods to treat segmental instability. We performed a nonsystematic review using the keywords "cervical spine surgery" and "history" and "instrumentation" and "fusion" in combination with "anterior approach" and "posterior approach," with no limit regarding the year of publication. Used databases were PubMed and Google Scholar. In addition, the search was extended by screening the reference list of all articles. Innovative surgical approaches allowed direct access to symptomatic areas of the cervical spine. Over the years, we observed a trend from posterior to anterior surgical techniques. Management of the degenerative spine has evolved from decompressive surgery alone to the direct removal of the cause of neural impingement. Internal fixation of actual or potential spinal instability and the associated instrumentation have continuously evolved to allow more reliable fusion. More recently, surgeons have developed the basis for nonfusion surgical techniques and implants. The most important advances appear to be (1) recognition of the need to directly address the causes of symptoms, (2) proper decompression of neural structures, and (3) more reliable fusion of unstable symptomatic segments.

The Position of the Aorta Relative to the Spine Before and After Anterior Instrumentation in Right Thoracic Scoliosis

Preoperative magnetic resonance images (MRI) and postoperative axial computed tomography (CT) scans in 25 consecutive patients with idiopathic right thoracic adolescent scoliosis (AIS) and anterior correction and fusion with a dual rod system were analyzed in a prospective study. Evaluation of the spatial relations between the vertebral body and the aorta and the relative migration of the aorta due to the anterior correction and instrumentation in right thoracic scoliosis patients. In anterior scoliosis surgery, bicortical screw purchase is performed to increase pullout strength. However, impingement of the aorta due to excessive contralateral screw penetration has been reported, especially after endoscopic instrumentation. For a safe screw placement, knowledge of both the preoperative topographic relation of aorta and vertebral body and its changes due to surgical correction is crucial. Recent studies reported on a more lateral and posterior position of the aorta in AIS patients. However, there are hardly any data on the changes of the aortic position after anterior curve correction available in the current literature. All 25 patients underwent an identical anterior surgical technique with standard open approach and dual rod instrumentation of the primary curve. Preoperative MRI and postoperative sequential CT scans of 180 vertebrae were analyzed with respect to following parameters: vertebral body width and depth, diameter of the aorta, closest distance between aorta and the vertebral body, the aorta-vertebral angle, and the position of the aorta in relation to the spinal canal. Before surgery, the aorta is positioned posterolaterally with an aorta-vertebral angle of between 78 degrees and 92 degrees (between T5 and T10). Between T11 and L2, the aorta is positioned more anteromedially with an aorta-vertebral angle from 62 degrees (T11) to 16 degrees (L2). After surgery, the aorta has migrated from a posterolateral to a more anteromedial position. This migration is maximal at the apex vertebra with an average change of the aorta-vertebral angle of 31.4 degrees . Whereas the distance between the aorta and the vertebral body increases at the upper and lower fusion levels, the aorta moves significantly closer to the vertebral body at the curve apex due to surgical correction. In patients with thoracic hypokyphosis, the aorta is positioned significantly more posterior than in patients with hyperkyphosis. This MRI and CT based study of 25 patients with thoracic AIS treated by standard open dual rod and dual screw instrumentation demonstrates a migration of the aorta by 31 degrees from a more posterolateral position before surgery to a more anteromedial position after surgery at the curve apex. Scoliosis surgeons should be aware of these changes; any excessive contralateral screw penetration must be avoided at any level.

Anterior Dual Rod Instrumentation in Idiopathic Thoracic Scoliosis

Axial computed tomography scans (CT) in 20 consecutive patients with idiopathic right thoracic scoliosis and anterior correction and fusion with a dual rod dual screw system. CT evaluation of screw position in anterior dual rod instrumentation relative to the aorta and the spinal canal. In anterior scoliosis surgery, bicortical screw purchase is used to increase pullout strength. However, impingement of the aorta due to excessive contralateral screw penetration has been reported, especially after endoscopic instrumentation. Data on the accuracy of dual screw instrumentation in thoracic scoliosis are missing. All 20 patients underwent an identical anterior surgical technique with double thoracotomy approach and dual rod instrumentation of the primary curve. Postoperative sequential CT scans were analyzed with respect to following parameters: vertebral body width and depth, diameter of the aorta, distance from the aorta to the closest point of the vertebral body cortex, distance between the tip of the screws and the aorta, distance between the screw and the spinal canal, and the amount of contralateral screw penetration. A total amount of 226 screws were evaluated. All screws were placed correctly without any critical proximity to the aorta or spinal canal. A total of 198 of 226 screws (88%) had a bicortical purchase. Thirteen screw tips (5.8%) were within 1 to 3 mm proximity to the aorta. All other screws were more than 3 mm distant from the aorta. The closest proximity of the screw tips to the thoracic aorta was found at the upper end vertebrae (T5, T6, or T7). There were no screws perforating the spinal canal. Anterior instrumentation and correction of thoracic scoliosis with a dual rod dual screw system enable a correct and safe screw placement using a standard open approach. Excessive bicortical screw perforation should be avoided in order not to endanger the thoracic aorta.

Dual-rod correction and instrumentation of idiopathic scoliosis with the Halm-Zielke instrumentation.

A prospective clinical and radiographic evaluation of 45 consecutive patients with idiopathic adolescent and adult scoliosis treated with anterior dual-rod Halm-Zielke instrumentation. Clinical and radiographic evaluation with a minimum follow-up of 2 years. Halm-Zielke instrumentation was developed to eliminate the disadvantages of Zielke instrumentation in terms of lack of primary stability and a kyphogenic effect. All patients underwent an identical anterior surgical technique with the Halm-Zielke instrumentation of the primary curve. The system is composed of a lid-plate, which is fixed to the lateral aspect of the vertebral body with two screws: a sunk screw anteriorly and a ventral derotation spondylodesis (VDS) screw posteriorly. The lid-plate design provides the lowest possible implant profile. The longitudinal components consist of a threaded rod and a solid, fluted rod. Correction is performed with both the threaded and the solid rod. The solid rod allows derotation and correction of the sagittal plane and provides primary stability. Preoperative curves ranged from 35 degrees to 92 degrees Cobb angle. Final correction of the frontal plane averaged 67% within the instrumented levels and 59% for the total primary curve. The apical vertebral rotation of the primary curve was corrected by 52% on average without loss of correction during follow-up. Thoracolumbar kyphosis was present in 11 patients and corrected in all cases from an average of 20 degrees to 2 degrees after surgery and to 8 degrees at follow-up. We observed two cases of implant failure with one resulting in a pseudarthrosis. Halm-Zielke instrumentation proved to be a major improvement of the original VDS-Zielke. It eliminates the kyphogenic effect and provides primary stability.

Surgical management of the lens and retrolenticular fibrotic membranes associated with persistent fetal vasculature

To evaluate a surgical technique that allows safe, effective, near-total removal of retrolenticular fibrotic membranes in eyes with persistent fetal vasculature syndrome (PFVS). Pediatric ophthalmologist's academic practice. This retrospective review comprised 5 children (6 eyes) who had excision of a retrolenticular fibrovascular membrane during cataract surgery over a 6-month period. Long, spoke-like radial incisions of the membrane were made to the ciliary processes, resulting in wedge-shaped segmentation of the membrane. A vitrector was used to excise each wedge and perform an anterior vitrectomy. The mean age at time of surgery was 8 months (range 1 to 24 months) and the mean follow-up, 9 months (range 2 to 13 months). The membrane was successfully removed in all eyes. One eye of a patient who did not comply with the postoperative medical regimen or follow-up developed pupillary block glaucoma requiring pupilloplasty and trabeculectomy. This anterior surgical technique to remove tenacious retrolenticular membranes associated with PFVS was effective, allowing near-total removal of the offending fibrovascular membrane.

Maintaining lumbar lordosis with anterior single solid-rod instrumentation in thoracolumbar and lumbar adolescent idiopathic scoliosis.

A prospective radiographic evaluation of 20 consecutive patients with primary lumbar or thoracolumbar adolescent idiopathic scoliosis who were treated with anterior convex compressive single solid-rod spinal instrumentation and structural titanium mesh (Harms) cages. To evaluate a lordosis-preserving anterior single solid-rod instrumented fusion technique for these specific adolescent idiopathic curves. Maintaining instrumented segmental lumbar lordosis after anterior fusion and instrumentation for thoracolumbar and lumbar curves has been difficult. Twenty consecutive patients who underwent anterior single solid-rod fusion, aged 18 or younger with a primary thoracolumbar or lumbar curve, were observed for preservation of lordosis for a minimum of 2 years. All patients underwent an identical anterior surgical technique, involving discectomies and anulectomies of all convex discs, structural titanium mesh (Harms) cages placed in the anterior half of all disc spaces below T12, morselized rib autograft packed in all disc spaces to be fused and inside the cages, and anterior single solid-rod (5.0-mm or 5.5-mm diameter) convex compressive spinal instrumentation with appropriate lordotic rod contour and rod rotation as necessary. The anterior rod was placed just posterior to the cages to optimize lordotic contouring of the spine during compression. None of the patients was braced after surgery. The lowest instrumented vertebrae (LIV) were L2 (n = 3), L3 (n = 15), and L4 (n = 2), typically the lower end vertebra of the Cobb measurement. Measurements for the primary coronal Cobb before surgery, 1 week after surgery, and 2 years after surgery were 48 degrees, 11 degrees, and 12 degrees; for C7 plumb line deviation from the midline: 3.6 cm, 1.9 cm, and 1.2 cm; for lowest instrumented vertebra translation: 31 mm, 15 mm, and 15 mm; and for LIV tilt: 29 degrees, 6 degrees and 6 degrees, respectively. Sagittal measurements before surgery, 1 week after surgery, and 2 years after surgery were: T12-L2: -1 degree, -6 degrees, and -6 degrees; T12-LIV: -8 degrees, -13 degrees, -9 degrees; T12-S1: -61 degrees, -56 degrees, -60 degrees; and entire instrumented levels: -6 degrees, -9 degrees, and -6 degrees, respectively. Coronal plane correction improved: 75% in the primary Cobb, 66% in the plumb line, 50% in LIV translation, and 80% in LIV tilt. Sagittal plane alignment improved in T12-L2 lordosis (P < 0.01) with preservation of physiologic lordosis in the instrumented levels, T12-LIV, and T12-sacrum. There were no instrumentation failures, pseudarthroses, or reoperations. Coronal plane correction with preservation of thoracolumbar and lumbar lordosis 2 years after anterior convex compressive spinal instrumentation was accomplished using a lordotically contoured single solid rod with structural cages placed anteriorly in the disc spaces of patients with primary thoracolumbar or lumbar adolescent idiopathic scoliosis.

Tuberculosis of the Spine

Chemotherapeutic agents remain the cornerstone of treatment for spinal tuberculosis. The arguments that surgery is necessary for biopsy and to allow for removal of infection and its byproducts have been usurped by advanced biopsy techniques and trials demonstrating resolution of infection and most abscesses using chemotherapy. Although chemotherapy alone has been demonstrated to be effective for some neurologic deficits, those lesions that may be safely treated without surgery remain to be fully defined. Modern imaging techniques have allowed more precise diagnosis and identification of neural compression and the extent of bony involvement. Refinement and popularization of anterior surgical techniques have made decompression and reconstruction relatively safe in experienced hands. Lesions that possess a propensity towards kyphosis are more readily identifiable. The use of instrumentation in the face of active disease appears to be promising, though at present there is a relative paucity of supporting data. Despite these advances in treatment, it must be borne in mind that ultimately, the diagnosis of this relatively uncommon disorder must precede the treatment.