Surgical considerations in posterior C1-2 instrumentation in the presence of vertebral artery anomalies: case illustration and review of literature.

Vascular anomalies involving the V3 segment of the vertebral artery are common and may complicate posterior atlantoaxial instrumentation. We report a patient with a fenestrated vertebral artery that underwent successful C1-2 instrumentation and fusion. Various vertebral artery anomalies are discussed with a review of pertinent literature.

Time to development, clinical and radiographic characteristics, and management of proximal junctional kyphosis following adult thoracolumbar instrumented fusion for spinal deformity.

STUDY DESIGN: A retrospective review. OBJECTIVE: To study time to development, clinical and radiographic characteristics, and management of proximal junctional kyphosis (PJK) following thoracolumbar instrumented fusion for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: PJK continues to be a common mode of failure following ASD surgery. Although literature exists on possible risk factors, data on management remain limited. METHODS: A retrospective review of medical records of 289 consecutive ASD patients who underwent posterior segmental instrumentation incorporating at least 5 segments was conducted. PJK was defined as proximal kyphotic angle >10 degrees. RESULTS: PJK occurred in 32 patients (11%) at a mean follow-up of 34 months (range, 1.3-61.9±19 mo). Sixteen (50%) patients were revised (mean, 1.7 revisions; range, 1-3) at a mean follow-up of 9.6 months (range, 0.7-40 mo); primary indications for revision were pain (n=16), myelopathy (n=6), instability (n=4), and instrumentation protrusion (n=2). Comparison of preindex and postindex surgery radiographic parameters demonstrated significant improvement in mean lumbar lordosis (24 vs. 42 degrees, P<0.001), pelvic incidence-lumbar lordosis mismatch (30 vs. 11 degrees, P<0.001), and pelvic tilt (29 vs. 23 degrees, P<0.011). The mean T5-T12 kyphosis worsened (30 vs. 53 degrees, P<0.001) and the mean global sagittal spinal alignment failed to improve (9.6 vs. 8.0 cm, P=0.76). There was no apparent relationship between the absolute PJK angle and revision surgery (P>0.05). CONCLUSIONS: The patients in this series who developed PJK had substantial preoperative positive sagittal malalignment that remained inadequately corrected following surgery, likely resulting from a combination of inadequate surgical correction and a significant compensatory increase in thoracic kyphosis. In the absence of direct relationship between a greater PJK angle and worse clinical outcome, clinical symptoms and neurological status rather than absolute reliance on radiographic parameters should drive the decision to pursue revision surgery.

Minimally invasive surgery for synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation.

Schwannomas are the most common intradural-extramedullary spinal tumors, with an estimated incidence of 3 to 10 cases per 100,000 people. With continued advances in minimally invasive surgery (MIS) over recent years, MIS techniques have been utilized by spine surgeons in the resection of intradural spinal neoplasms with favorable surgical results and clinical outcomes. This video demonstrates a rare case of symptomatic, synchronous, same-level lumbar intradural-extramedullary neoplasm and acute disc herniation, both of which were successfully treated using a single MIS approach. Surgical pearls and nuances are discussed to better delineate technique and minimize potential complications. The video can be found here: http://youtu.be/78ibbicBRUk.

Surgical resection of subependymoma of the cervical spinal cord.

Subependymomas can rarely occur in the spinal cord, and account for about 2% of symptomatic spinal cord tumors. It most often occurs in the cervical spinal cord, followed by cervicothoracic junction, thoracic cord and conus medullaris. It often has an eccentric location in the spinal cord and lacks gadolinium enhancement on magnetic resonance imaging. We present a rare case of symptomatic subependymoma of the cervical spinal cord, which underwent successful gross total resection. Surgical pearls and nuances are discussed to help surgeons to avoid potential complications. The video can be found here: http://youtu.be/Rsm9KxZX7Yo.

Evolution and current status of surgical management of thoracic disc herniation - A review.

Thoracic disc herniations (TDH) are uncommon compared to cervical and lumbar disc herniations. Surgical treatment of TDH can be challenging due to the anatomical constraints and the high risk of morbidity due to proximity to the thoracic spinal cord. Moreover, the selection of appropriate surgical approach depends on various factors such as the size and location of disc herniation within the spinal canal, spinal level, presence or absence of calcification, degree of spinal cord compression, and familiarity with various approaches by the treating surgeon. While there is agreement that posterolateral approaches can be used to treat posterolateral and central soft disc herniation, there is a lack of consensus on the best surgical approach for central calcified and giant calcified TDH where an anterior approach is perceived as the best option. There is increasing evidence that support the safety and efficacy of posterolateral approaches even for central calcified and giant calcified TDH. This review highlights the evolution of surgical management for TDH based on the past and current literature and the author's experience at his institution.

The 5-Item Modified Frailty Index as a Predictor of Postoperative Outcomes in Thoracic Metastatic Epidural Spinal Cord Compression.

BACKGROUND: Patients with thoracic metastatic epidural spinal cord compression (MESCC) often undergo extensive surgical decompression to avoid functional decline. Though limited in scope, scales including the revised cardiac risk index (RCRI) are used to stratify surgical risk to predict perioperative morbidity. This study uses the 5-item modified frailty index (mFI-5) to predict outcomes following transpedicular decompression/fusion for high-grade MESCC. METHODS: A retrospective chart review was conducted on patients who underwent transpedicular decompression and fusion for MESCC (baseline demographics, spinal instability neoplastic score, preoperative and postoperative Bilsky scores, primary cancer type, and RCRI). Primary outcomes included length of stay (LOS), intraoperative estimated blood loss, readmission/reoperation within 90 days of index surgery, 90-day mortality, and posthospitalization disposition. RESULTS: One hundred twenty-seven patients were included in our study. Ninety percent of patients' lesions were Bilsky 2 or greater. Increasing frailty, measured by mFI-5, was a significant predictor of increased LOS (P < 0.01) and 90-day mortality (P < 0.05). Multivariate analysis adjusting for sex, body mass index , and age still showed statistical significance (P < 0.05). MFI-5 was not a significant predictor of readmission/reoperation within 90 days or estimated blood loss. Age - not mFI-5 or RCRI - was a significant predictor for posthospitalization nonhome disposition (P = 0.001). CONCLUSIONS: The mFI-5 can serve as a useful predictor of outcomes after transpedicular decompression and fusion for thoracic MESCC as it can account for the patient's frailty. Our study demonstrated the mFI-5 as a predictor of LOS and 90-day mortality. These results provide a background to both understanding and integrating frailty into decision-making in MESCC.

Indication as a predictor for outcomes in anterior cervical discectomy and fusion: The impact of myelopathy on disposition.

BACKGROUND: While the indication for Anterior Cervical Discectomy and Fusion (ACDF) may influence the expected postoperative course, there is limited data comparing how length of stay (LOS) and disposition for patients with myelopathy differ from those with radiculopathy. This study aimed to compare LOS and discharge disposition, in patients undergoing ACDF for cervical radiculopathy versus those for myelopathy. METHODS: A retrospective review of all adult ACDF cases between 2013 and 2019 was conducted analyzing sex, age, race, comorbidities, level of surgery, myelopathy measures when applicable, complications, dysphagia, hospital LOS, and discharge disposition. RESULTS: A total of 157 patients were included in the study with 73 patients undergoing an ACDF for radiculopathy and 84 for myelopathy. Univariate analysis determined older age (p < 0.01), male sex (p = 0.03), presence of CKD (p < 0.01) or COPD (p = 0.01), surgery at C3/4 level (p = 0.01), and indication (p < 0.01) as predictors for a discharge to either acute rehabilitation or a skilled nursing facility rather than to home. Multivariate logistic regression demonstrated age and indication as the only independent predictors of disposition, with home disposition being more likely with decreased age (OR 0.92, 95 % CI 0.86-0.98) and radiculopathy as the diagnosis (OR 6.72, 95 % CI 1.22- 37.02). CONCLUSIONS: Myelopathic patients, as compared to those with radiculopathy at presentation, had significantly longer LOS, increased dysphagia, and were more often discharged to a facility. Understanding these two distinct populations as separate entities will streamline the pre and post-surgical care as the current DRG codes and ICD 10 PCS do not differentiate the expected post-operative course in patients undergoing ACDF for myelopathy versus radiculopathy.

Risk factors for C5 palsy: a systematic review and multivariate analysis.

OBJECTIVE: Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P. METHODS: A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website. RESULTS: Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low. CONCLUSIONS: The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).

Failure of porous tantalum cervical interbody fusion devices: two-year results from a prospective, randomized, multicenter clinical study.

OBJECTIVE: The objective of this study was to assess the safety and efficacy of 2 novel cervical interbody fusion devices in the treatment of single-level degenerative cervical disk disease. Both devices were fabricated from a porous tantalum material. The high overall porosity of the devices was intended to facilitate anterior cervical interbody fusion. METHODS: A prospective, randomized, 3-armed, clinical study was initiated with the following treatment groups: porous tantalum ring device packed with autograft, porous tantalum block device, and iliac crest autograft control. All the patients had single-level symptomatic cervical disk disease that had failed to respond to nonoperative therapy. Clinical and radiographic data were collected preoperatively, during surgery, before hospital discharge, and at 6 weeks, 3 months, 6 months, 12 months, and 24 months postoperatively. RESULTS: Six investigators participated in the clinical study at 6 investigational centers in the United States. Enrollment into the study was terminated after 39 patients had been accrued because of concerns over delayed fusion in the porous tantalum treatment groups. Of the 39 patients enrolled into the clinical study, 11 patients received the control treatment of iliac autograft fusion, 13 patients received the porous tantalum ring device with the center cavity packed with cancellous iliac crest autograft, and 15 patients received the porous tantalum block device. These patients were evaluated for 24 months as per the study protocol. There were no significant differences in any of the patient demographic variables collected. The mean operative times for both the ring and block device groups were slightly lower than the control treatment. Two patients in the block treatment group were determined to be nonunion between the 6- and 12-month time points and underwent additional surgery. Five patients with porous tantalum devices showed radiographic evidence of device fragmentation, and one patient in addition had radiographic evidence of erosion of the involved vertebral bodies by the device. One patient in the ring treatment group died from a myocardial infarction and kidney failure subsequent to the 12-month follow-up visit, which was unrelated to the device or the spinal fusion procedure. Fusion rate at 2 years for the tantalum device was very low as compared with the control arm (44% vs. 100%). Patient Neck Disability Index scores, Short Form-36 scores, and neurological status scores were similar between the 3 treatment groups. CONCLUSIONS: This study demonstrates that stand-alone porous tantalum material is not ideal for a cervical spine interbody fusion because of the low rate of arthrodesis and the risk of device fragmentation in patients who fail to fuse.

Abnormal L5-S1 Facet Joint Orientation as a Harbinger of Degenerative Spondylolisthesis: A Case Report.

Degenerative spondylolisthesis is a common cause of low back pain and resultant disability in the adult population. The causes of degenerative spondylolisthesis are not entirely understood, though a combination of anatomic and lifestyle factors likely contributes to the development of this pathology. Here, we report a case of a 38-year-old female presenting with low back pain and right lower extremity radiculopathy, found to have degenerative L5-S1 spondylolisthesis, which we postulate developed in part due to the sagittal orientation of her L5-S1 facet joints bilaterally.

Effect of total lumbar disc replacement on lumbosacral lordosis.

STUDY DESIGN: Original article OBJECTIVE: : To study effect of lumbar disc replacement on lumbosacral lordosis. SUMMARY OF BACKGROUND DATA: There has been a growing interest in total disc replacement (TDR) for back pain with the rising concern of adjacent segment degeneration. Lumbar fusion surgery has been shown to lead to decrease in lumbar lordosis, which may account for postfusion pain resulting in less acceptable clinical outcome after successful fusion. TDR has recently emerged as an alternative treatment for back pain. There have been very few studies reporting lumbar sagittal outcome after TDR. METHODS: Retrospective study of radiographic data of 17 patients who underwent TDR for single level degenerative disc disease at the author's institution was carried out. Study included measurement of preoperative and postoperative segmental and global lumbar lordosis and angle of lordosis. RESULTS: Patients age varied from 19 to 54 (mean, 35) years. Follow-up ranged from 12 to 24 months. TDR was performed at L4-5 level in 3 patients and L5-S1 level in 14 patients. The average values for segmental lordosis, global lordosis, and angle of lordosis at the operated level before and after surgery were 17.3, 49.7, and 8.6 degrees and 21.6, 54, and 9.5 degrees, respectively. There was a trend toward significant (P=0.02) and near significant (P=0.057) increase in segmental and global lordosis, respectively after TDR. Although prosthesis increased angle of lordosis at the level implanted in majority of the patients, the difference in preoperative and postoperative angle of lordosis was not significant (P=0.438). In addition, there was no correlation between the angle of implant of chosen and postoperative angle of lordosis at the operated level. CONCLUSIONS: The effect of TDR on sagittal balance appears favorable with an increase in global and segmental lumbar lordosis after single level TDR for degenerative disc disease. The degree of postoperative angle of lordosis was not affected by the angle of implant chosen at the operated level and varied independently of the implant angle.

Posterior-only approach for the treatment of symptomatic central thoracic disc herniation regardless of calcification: A consecutive case series of 30 cases over five years.

PURPOSE: To report the safety and efficacy of posterolateral approach for thoracic disc herniation (TDH) via a consecutive clinical case series of 30 central thoracic disc herniations that were all operated through a posterolateral approach. METHODS: A retrospective review was conducted of all patients with symptomatic TDH who underwent surgical intervention from 2016 to 2021. A total of 23 patients comprising 30 central TDH were included in the study. Age, gender, location of the lesion, preoperative and post-operative Frankel and Nurick scores, surgical approach and instrumented vertebrae, and length of stay were recorded. FINDINGS: 23 patients with an average age of 62 were included in the study. 30 of the 32 symptomatic TDH were centrally located. 8/32 TDH were calcified while 24/32 TDH were non-calcified. Unilateral and bilateral transpedicular approach was used in the treatment of 12/32 and 10/32 disc herniations respectively. A transfacet-pedicle sparing approach was used in 10/32 disc herniations. 19/23 (82.6%) of the patients had improvement in Nurick score while 12/23 (52.2%) patients had improvement in their Frankel scores. The average length of stay was 4.5 days. No major complications were encountered. All patients underwent a short-segment instrumented construct with no need for revision surgery for thoracic disc herniation, worsening myelopathy, or instrumentation failure. CONCLUSIONS: 83% of the patients who underwent a transfacet or transpedicular decompression for the treatment of symptomatic TDH had improvement in their myelopathy with no neurological deterioration in any of the patients. Given the familiarity and low morbidity associated with a transfacet or transpedicular approach, posterolateral-based approaches remains an excellent alternative for surgical management of majority of the patients with thoracic disc herniations.

Outcomes and complications following minimally invasive excision of synovial cysts of the lumbar spine: A systematic review and meta-analysis.

OBJECTIVE: Lumbar synovial cysts (LSC) are one of the manifestations of spinal degenerative cascade. Spinal stenosis or presence of instability in these patients can lead to various symptoms and surgery is indicated following failure of non-operative management for symptomatic synovial cysts. Surgery when performed consists of either decompression with resection of cyst with our without fusion. The efficacy and complications of minimally invasive techniques using tubular retractors (microscopic or endoscopic) in comparison to traditional open techniques remain to be studied. METHODS: A comprehensive search of different databases was performed to retrieve studies describing the use of minimal invasive techniques using tubular retractors (both microscopic and endoscopic) in patients with LSC. Meta-analysis with subgroup analysis and metaregression was done. RESULTS: Twenty articles were selected for the systematic review and meta-analysis with total of 388 patients. Eighty-six percent of patients (95% Confidence Interval (CI): 80-90%) had favorable outcome as per Macnab's criteria (excellent and good outcome) with the pooled standard mean difference between preoperative and postoperative Oswestry Disability Index (ODI) being -4.44 (95% CI -8.78 to -0.10, p-value=0.0474, I2 82%). The pooled percentage change in visual analogue scale (VAS) after surgery was 76.5% (95% CI 66.9-84%, I2 82%). The pooled proportion of incidental durotomies, cyst recurrence and patients requiring operation being 8% (95% CI 5-11%, I2 0%), 4% (95% CI 2-7%, I2 0%,) and 5% (95% CI 3-9%) respectively. Studies were homogeneous with an I2 value of 0%. Subgroup analysis revealed no significant difference in the outcome rates or complication rates between the microscopic and endoscopic subgroups. CONCLUSION: Minimally invasive techniques for the resection of LSC is a safe and effective alternative to traditional surgical approaches with no difference between the microscopic and endoscopic approaches.