Amit K. Sharma

Indirect foraminal decompression after lateral transpsoas interbody fusion.

OBJECT Lateral transpsoas interbody fusion (LTIF) permits anterior column lumbar interbody fusion via a direct lateral approach. The authors sought to answer 3 questions. First, what is the effect of LTIF on lumbar foraminal area? Second, how does interbody cage placement affect intervertebral height? And third, how does the change in foraminal area and cage position correlate with changes in Oswestry Disability Index (ODI) and 12-Item Short Form Health Survey (SF-12) scores? METHODS Included patients underwent LTIF with or without posterior instrumentation and received preoperative and postoperative CT scans. Disc heights, neural foraminal area between adjacent-level pedicles, and anteroposterior cage position were measured from sagittal CT images. Preoperative and postoperative ODI and SF-12 scores were matched with the change in foraminal area from the clinically most severely affected side for analysis of the relationship between outcomes instruments and change in foraminal area. RESULTS Average foraminal area increased by 36.2 mm(2), or 35% of the preoperative area (p < 0.01), without statistically significant differences by side, level, or anteroposterior cage position. Preoperative anterior and posterior disc heights measured 6.2 mm and 3.7 mm, respectively, compared with postoperative measurements of 9.8 mm (p < 0.01) and 6.3 mm (p < 0.01), respectively, without significant differences by level or cage position. Despite significant overall improvement in ODI and SF-12 scores, there was no correlation with foraminal area increase. CONCLUSIONS Average foraminal area increased approximately 35% after cage placement without variation based on cage position. While ODI and SF-12 scores increased significantly, there was no significant association with cage position or foraminal area change, likely attributable to the multifactorial nature of preoperative pain.

Lateral transpsoas interbody fusion (LTIF) with plate fixation and unilateral pedicle screws: a preliminary report.

Study Design Retrospective cohort study. Objective We present the radiographic and clinical outcomes of 13 patients who underwent lateral transpsoas interbody fusion (LTIF) stabilized by unilateral pedicle screw instrumentation and anterior instrumentation. Summary of Background Data LTIF is a surgical technique that permits anterior column lumbar interbody fusion via a direct lateral transpsoas approach. Because of the inherent stability of the implants used and the minimal disruption of stabilizing ligaments associated with LTIF, this technique may allow use of less invasive adjunctive fixation methods including unilateral pedicle screw fixation. Methods Information from medical records included patient demographics, medical comorbidities, clinical assessment, surgical time, blood loss, implant information, and complications. Oswestry Disability Index, Short Form-12, and visual analog pain scale scores were obtained. Postoperative imaging allowed assessment of fusion, subsidence, and alignment. Results Estimated blood loss averaged 225 mL and operative time averaged 261 minutes. No patients received a transfusion. Average length of hospital stay was 4.6 days. Oswestry Disability Index, Short Form-12, and visual analog pain scores demonstrated significant improvement. All patients with available 1 year postoperative imaging demonstrated solid fusion with average cranial and caudal subsidence of 1.8 and 0.8 mm, respectively. Two patients developed postoperative nondisplaced vertebral fractures through the anterior fixation screw tracts. Three patients developed transient postoperative hip flexion weakness and one also developed transient hypoesthesia in the anterior thigh, likely approach related. Conclusions We report a series of patients treated with unilateral pedicle screw fixation with LTIF. Although the patient cohort is small, validated outcomes instruments were used and fusion was assessed by computed tomography scan in most cases. The data suggest that unilateral pedicle screw fixation may be adequate to achieve high fusion rates after LTIF surgery using anterior instrumentation. Applying this technique in patients with osteoporosis may lead to a significant risk of postoperative vertebral body fracture.

Factors influencing segmental lumbar lordosis after lateral transpsoas interbody fusion.

Although contributions to sagittal alignment have been characterized for anterior, posterior and transforaminal lumbar interbody fusion, sagittal alignment after lateral transpsoas interbody fusion (LTIF) has not yet been characterized. This study examined the ability of LTIF to restore lumbar lordosis and identified factors associated with change in sagittal alignment.

Omega-3 and fish oil supplements do not cause increased bleeding during spinal decompression surgery.

Study Design Retrospective case-control study. Objective The purpose of this study was to assess whether preoperative use of fish oil supplements increases intraoperative blood loss and postoperative bleeding complications during lumbar decompression surgery. Summary of Background Data Omega-3 fatty acids (n-3FA) are widely used as over-the-counter supplements because of well-established cardioprotective and antiplatelet effects. Concern over bleeding associated with changes in platelet function have led to prohibiting these supplements before surgery although there are no clinical data available in the spinal surgery literature to guide such recommendations. Methods Ninety-five consecutive patients who underwent posterior-only lumbar decompression by a single surgeon were included. Patients who had taken n-3FA within 14 days of surgery were compared with a control group with respect to demographics, preoperative use of other anticoagulants, surgical time, estimated intraoperative blood loss, and postoperative complications including reoperation for epidural hematoma and wound infection. Power analysis suggested 11 patients taking n-3FA were necessary to reach statistical significance based on pilot data. Results Sixteen patients took n-3FA supplements, stopping an average of 2.3 days before surgery. These were no significant between-group differences in demographic parameters, use of other anticoagulants, and surgical time. Estimated blood loss was higher in the control group but the difference was not significant (154 vs. 138 mL, P=0.53). There were 2 complications related to bleeding in the control group and none in the n-3FA group. Conclusions We found no increase in intraoperative blood loss or postoperative bleeding complications associated with preoperative use of n-3FA supplements up to an average of 2.3 days before surgery. Although further studies are necessary before this finding can be generalized to other types of spinal surgery, our study corroborates findings from investigations in other surgical specialties that suggest preoperative n-3FA is not associated with increased risk of intraoperative and postoperative bleeding.

Two-stage exchange for infected resurfacing arthroplasty: use of a novel cement spacer technique.

Infection after total hip arthroplasty is a devastating complication. A 2-stage reimplantation with antibiotic-impregnated interval spacer is typically recommended. We present a case of infected resurfacing hip arthroplasty treated with a novel cement spacer technique. The aim was to avoid the introduction of the infection into the femoral medullary canal with the use of a conventional stemmed antibiotic cement spacer. Reimplantation was accomplished routinely, and the patient remains infection-free at 9 months.

Do lordotic cages provide better segmental lordosis versus non-lordotic cages in lateral lumbar interbody fusion (llif)?

Study Design: A retrospective comparative radiographic review. Objective: To evaluate the radiographic changes brought about by lordotic and nonlordotic cages on segmental and regional lumbar sagittal alignment and disk height in lateral lumbar interbody fusion (LLIF). Summary of Background Data: The effects of cage design on operative level segmental lordosis in posterior interbody fusion procedures have been reported. However, there are no studies comparing the effect of sagittal implant geometry in LLIF. Methods: This is a comparative radiographic analysis of consecutive LLIF procedures performed with use of lordotic and nonlordotic interbody cages. Forty patients (61 levels) underwent LLIF. Average age was 57 years (range, 30–83 y). Ten-degree lordotic PEEK cages were used at 31 lumbar interbody levels, and nonlordotic cages were used at 30 levels. The following parameters were measured on preoperative and postoperative radiographs: segmental lordosis; anterior and posterior disk heights at operative level; segmental lordosis at supra-level and subjacent level; and overall lumbar (L1–S1) lordosis. Measurement changes for each cage group were compared using paired t test analysis. Results: The use of lordotic cages in LLIF resulted in a significant increase in lordosis at operative levels (2.8 degrees; P=0.01), whereas nonlordotic cages did not (0.6 degrees; P=0.71) when compared with preoperative segmental lordosis. Anterior and posterior disk heights were significantly increased in both groups (P<0.01). Neither cage group showed significant change in overall lumbar lordosis (lordotic P=0.86 vs. nonlordotic P=0.25). Conclusions: Lordotic cages provided significant increase in operative level segmental lordosis compared with nonlordotic cages although overall lumbar lordosis remained unchanged. Anterior and posterior disk heights were significantly increased by both cages, providing basis for indirect spinal decompression.