Clinical and Short-Term Radiographic Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion With Expandable Lordotic Devices

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is a well-accepted procedure for the treatment of degenerative lumbar disease. However, its ability to restore lumbar lordosis has been limited. Development of expandable lordotic interbody devices has challenged this limitation, furthering the scope of minimally invasive surgery.

OBJECTIVE

To evaluate the radiographic and clinical effects of expandable lordotic interbody devices placed through an MIS-TLIF approach.

METHODS

We conducted a retrospective review of 32 1-level and 18 2-level MIS-TLIFs performed using lordotic expandable interbody devices. Lumbar radiographic measurements, Oswestry Disability Index scores (ODI), and Visual Analogue Scale scores (VAS) were obtained at preoperative, 6 wk follow up, and last follow up time points. Last follow up occurred at a mean of 11.5 ± 7.6 mo (mean ± SD).

RESULTS

At 6-wk follow-up, segmental lordosis, disc height, and foraminal height increased by an average of 3.4°, 6.4 mm, and 4.4 mm, respectively. Only the 2-level group showed a significant increase in lumbar lordosis of 5.8°. No significant changes occurred in sacral slope, pelvic tilt, or pelvic incidence. Average ODI and VAS decreased by -12.0 and -4.5, respectively. Postoperative lumbar lordosis inversely correlated with preoperative lordosis in patients with an initial Pelvic Incidence to Lumbar Lordosis mismatch (PI-LL) of >10°, (r = -0.5, P = .009).

CONCLUSION

When applied across 2-levels, MIS-TLIF using expandable lordotic interbody devices produced a significant increase in lumbar lordosis. Preoperative lumbar lordosis was found to be a predictor of postoperative lumbar lordotic change in patients with sagittal imbalance.

Minimally Invasive Transforaminal Lumbar Interbody Fusion: 2-Dimensional Surgical Video

This operative video is a detailed look at minimally invasive transforaminal lumbar interbody fusion. We provide a step-by-step guide with appropriate narration and operative video to enhance the educational experience. We review clinical and radiographic evaluation, patient positioning, intraoperative navigation, localization, percutaneous pedicle screw placement, minimally invasive approach, disc space preparation, placement of interbody device, and closure. By presenting up-to-date minimally invasive and intraoperative navigation techniques, this video provides educational benefit to all neurosurgeons regardless of training level.

Cervical radiographic parameters in 1- and 2-level anterior cervical discectomy and fusion

OBJECTIVE

Anterior cervical discectomy and fusion (ACDF) is one of the most commonly performed spine procedures. It can be used to correct cervical kyphotic deformity, which is the most common cervical deformity, and is often performed using lordotic interbody devices. Worsening of the cervical sagittal parameters is associated with decreased health-related quality of life. The study hypothesis is that through the use of machined lordotic allografts in ACDF, segmental and overall cervical lordosis can be maintained or increased, which will have a positive impact on overall cervical sagittal alignment.

METHODS

Seventy-four cases of 1-level ACDF (ACDF1) and 2-level ACDF (ACDF2) (40 ACDF1 and 34 ACDF2 procedures) were retrospectively reviewed. Upright neutral lateral radiographs were assessed preoperatively and at 6 weeks and 1 year postoperatively. The measured radiographic parameters included focal lordosis, disc height, C2–7 lordosis, C1–7 lordosis, T-1 slope, and C2–7 sagittal vertical axis. Correlation coefficients were calculated to determine the relationships between these radiographic measurements.

RESULTS

The mean values were as follows: preoperative focal lordosis was 0.574°, disc height was 4.48 mm, C2–7 lordosis was 9.66°, C1–7 lordosis was 42.5°, cervical sagittal vertebral axis (SVA) was 26.9 mm, and the T-1 slope was 33.2°. Cervical segmental lordosis significantly increased by 6.31° at 6 weeks and 6.45° at 1 year. C2–7 lordosis significantly improved by 1 year with a mean improvement of 3.46°. There was a significant positive correlation between the improvement in segmental lordosis and overall cervical lordosis. Overall cervical lordosis was significantly negatively correlated with cervical SVA. Improved segmental lordosis was not correlated with cervical SVA in ACDF1 patients but was significantly negatively correlated in ACDF2 patients. There was also a significant positive correlation between the T-1 slope and cervical SVA.

CONCLUSIONS

In the study population, the improvement of focal lordosis was significantly correlated with an improvement in overall lordosis (C1–7 and C2–7), and overall lordosis as measured by the C2–7 Cobb angle was significantly negatively correlated with cervical SVA. Using lordotic cervical allografts, we successfully created and maintained significant improvement in cervical segmental lordosis at the 6-week and 1-year time points with values of 6.31° and 6.45°, respectively. ACDF is able to achieve statistically significant improvement in C2–7 cervical lordosis by the 1-year followup, with a mean improvement of 3.46°. Increasing the number of levels operated on resulted in improved cervical sagittal parameters. This establishes a baseline for further examination into the ability of multilevel ACDF to achieve cervical deformity correction through the intervertebral correction of lordosis.

Intramedullary Spinal Cord Tumors: Part II-Management Options and Outcomes

Study Design Broad narrative review. Objectives Intramedullary spinal cord tumors (IMSCT) are uncommon lesions that can affect any age group or sex. However, numerous IMSCT exist and the clinical course of each tumor varies. The following article addresses the various management options and outcomes in patients with IMSCT. Methods An extensive review of the peer-reviewed literature was performed, addressing management options and clinical outcomes of patients with IMSCT. Results Early diagnosis and intervention are essential to obtain optimal functional outcome. Each IMSCT have specific imaging characteristics, which help in the clinical decision-making and prognostication. A comprehension of the tumor pathology and the clinical course associated with each tumor can allow for the proper surgical and nonsurgical management of these tumors, and reduce any associated morbidity and mortality. Recent advances in the operative management of such lesions have increased the success rate of tumor removal while minimizing iatrogenic-related trauma to the patient and, in tandem, improving patient outcomes. Conclusions Awareness and understanding of IMSCT is imperative to design proper management and obtain optimal patient outcomes. Meticulous operative technique and the use of surgical adjuncts are essential to accomplish proper tumor removal, diminish the risk of recurrence, and preserve neurologic function. Operative management of IMSCT should be individualized and based on tumor type, location, and dimensional extensions. To assist with preoperative and intraoperative decision-making, a general algorithm is provided.

Secondary malignancy following radiotherapy for thyroid eye disease

AIM

To describe the first case of a secondary meningioma in a patient after radiation treatment for thyroid eye disease (TED). Secondarily to identify any additional cases of secondary malignancy resulting from radiotherapy for thyroid eye disease from our institutional experience.

BACKGROUND

Thyroid eye disease (TED) is a self-limiting auto-immune disorder causing expansion of orbital soft tissue from deposition of glycosaminoglycans and collagen, leading to significant cosmetic and functional morbidity. Established management options for TED include: glucocorticosteroids, orbital radiotherapy, and surgical orbital decompression. Two large series on radiotherapy for TED have been reported without any cases of secondary malignancy.

MATERIALS AND METHODS

The case of a patient with visual failure, found to have a sphenoid wing meningioma after previous TED radiotherapy is described. We then reviewed 575 patients with at least 3-year follow-up receiving radiotherapy for TED at British Columbia Cancer Agency to identify other possible secondary malignancies.

RESULTS

The patient had postoperative improvement in her vision without any identified complications. Three additional cases of hematologic malignancy were identified. The calculated risk in our population of developing a radiation-induced meningioma after TED with at least 3 years of follow-up of is 0.17% (1/575); with hematopoetic malignancies the risk for secondary malignancy is 0.7% (4/575).

CONCLUSIONS

Our calculated risk for secondary malignancy (0.17%, 0.7%) is similar to the reported theoretical risk published in the literature (0.3-1.2%). There is real risk for the development of a secondary malignancy after radiotherapy treatment of TED and treatment options should include consideration for this potential.

Intramedullary Spinal Cord Tumors: Part I-Epidemiology, Pathophysiology, and Diagnosis

Study Design Broad narrative review. Objectives Intramedullary spinal cord tumors (IMSCT) are rare neoplasms that can potentially lead to severe neurologic deterioration, decreased function, poor quality of life, or death. As such, a better understanding of these lesions is needed. The following article, part one of a two-part series, addresses IMSCT with regards to their epidemiology, histology, pathophysiology, imaging characteristics, and clinical manifestations. Methods The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. Results Numerous IMSCT exist with varying epidemiology. Each IMSCT has its own hallmark characteristics and may vary with regards to how aggressively they invade the spinal cord. These lesions are often difficult to detect and are often misdiagnosed. Furthermore, radiographically and clinically, these lesions may be difficult to distinguish from one another. Conclusions Awareness and understanding of IMSCT is imperative to facilitate an early diagnosis and plan management.

Pelvic reconstruction after subtotal sacrectomy for sacral chondrosarcoma using cadaveric and vascularized fibula autograft: Technical note

A novel method of spinopelvic ring reconstruction after partial sacrectomy for a chondrosarcoma is described. Chondrosarcoma is one of the most common primary malignant bone tumors, and en bloc resection is the mainstay of treatment. Involvement of the pelvis as well as the sacrum and lumbar spine can result in a technically difficult challenge for en bloc resection and for achievement of appropriate load-bearing reconstruction. After en bloc resection in their patient, the authors achieved reconstruction with a rod and screw construct including vascularized fibula graft as the main strut from the lumbar spine to the pelvis. Additionally, a cadaveric allograft strut was used as an adjunct for the pelvic ring. This is similar to a modified Galveston technique with vascularized fibula in place of the Galveston rods. The vascularized fibula provided appropriate biomechanical support, allowing the patient to return to independent ambulation. There was no tumor recurrence; neurological status remained stable; and the allograft construct integrated well and even increased in size on CT scans and radiographs in the course of a follow-up longer than 7 years.