Does the ACS NSQIP Surgical Risk Calculator Accurately Predict Complications Rates After Anterior Lumbar Interbody Fusion Procedures?

STUDY DESIGN: Clinical case series. OBJECTIVE: The aim of this study was to determine the effectiveness of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) surgical risk calculator in the prediction of complications after anterior lumbar interbody fusion (ALIF). SUMMARY OF BACKGROUND DATA: Identifying at-risk patients may aid in the prevention of complications after spine procedures. The ACS NSQIP surgical risk calculator was developed to predict 30-day postoperative complications for a variety of operative procedures. METHODS: Medical records of patients undergoing ALIF at our institution from 2009 to 2019 were retrospectively reviewed. Demographic and comorbidity variables were entered into the ACS NSQIP surgical risk calculator to generate percentage predictions for complication incidence within 30 days postoperatively. The observed incidences of these complications were also abstracted from the medical record. The predictive ability of the ACS NSQIP surgical risk calculator was assessed in comparison to the observed incidence of complications using area under the curve (AUC) analyses. RESULTS: Two hundred fifty-three (253) patients were analyzed. The ACS NSQIP surgical risk calculator was a fair predictor of discharge to non-home facility (AUC 0.71) and surgical site infection (AUC 0.70). The ACS NSQIP surgical risk calculator was a good predictor of acute kidney injury/progressive renal insufficiency (AUC 0.81). The ACS NSQIP surgical risk calculator was not an adequate predictive tool for any other category, including: pneumonia, urinary tract infections, venous thromboembolism, readmission, reoperations, and aggregate complications (AUC < 0.70). CONCLUSION: The ACS NSQIP surgical risk calculator is an adequate predictive tool for a subset of complications after ALIF including acute kidney injury/progressive renal insufficiency, surgical site infections, and discharge to non-home facilities. However, it is a poor predictor for all other complication groups. The reliability of the ACS NSQIP surgical risk calculator is limited, and further identification of models for risk stratification is necessary for patients undergoing ALIF.Level of Evidence: 3.

Local versus distal transplantation of human neural stem cells following chronic spinal cord injury.

BACKGROUND CONTEXT: Previous studies have demonstrated functional recovery of rats with spinal cord contusions after transplantation of neural stem cells adjacent to the site of acute injury. PURPOSE: The purpose of the study was to determine if the local or distal injection of neural stem cells can cause functional difference in recovery after chronic spinal cord injury. STUDY DESIGN/SETTING: Twenty-four adult female Long-Evans hooded rats were randomized into four groups, with six animals in each group: two experimental and two control groups. Functional assessment was measured after injury and then weekly for 6 weeks using the Basso, Beattie, and Bresnahan locomotor rating score. Data were analyzed using two-sample t test and linear mixed-effects model analysis. METHODS: Posterior exposure and laminectomy at the T10 level was used. Moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor with 10-g weight dropped from a height of 25 mm. Experimental subjects received either a subdural injection of human neural stem cells (hNSCs) locally at the injury site or intrathecal injection of hNSCs through a separate distal laminotomy 4 weeks after injury. Controls received control media injection either locally or distally. RESULTS: A statistically significant functional improvement in subjects that received hNSCs injected distally to the site of injury was observed when compared with the control (p=.042). The difference between subjects that received hNSCs locally and the control did not reach statistical significance (p=.085). CONCLUSIONS: The transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected distally but not locally to the site of chronic spinal cord injury.

Does provocative discography cause clinically important injury to the lumbar intervertebral disc? A 10-year matched cohort study.

BACKGROUND CONTEXT: Provocative discography, an invasive diagnostic procedure involving disc puncture with pressurization, is a test for presumptive discogenic pain in the lumbar spine. The clinical validity of this test is unproven. Data from multiple animal studies confirm that disc puncture causes early disc degeneration. A recent study identified radiographic disc degeneration on magnetic resonance imaging (MRI) performed 10 years later in human subjects exposed to provocative discography. The clinical effect of this disc degeneration after provocative discography is unknown. PURPOSE: The aim of this study was to investigate the clinical effects of lumbar provocative discography on patients subjected to this evaluation method. STUDY DESIGN/SETTING: A prospective, 10-year matched cohort study. PATIENT SAMPLE: Subjects (n=75) without current low back pain (LBP) problems were recruited to participate in a study of provocative discography at the L3-S1 discs. A closely matched control cohort was simultaneously recruited to undergo a similar evaluation except for discography injections. OUTCOME MEASURES: The primary outcome variables were diagnostic imaging events and lumbar disc surgery events. The secondary outcome variables were serious LBP events, disability events, and medical visits. METHODS: The discography subjects and control subjects were followed by serial protocol evaluations at 1, 2, 5, and 10 years after enrollment. The lumbar disc surgery events and diagnostic imaging (computed tomography (CT) or MRI) events were recorded. In addition, the interval and cumulative lumbar spine events were recorded. RESULTS: Of the 150 subjects enrolled, 71 discography subjects and 72 control subjects completed the baseline evaluation. At 10-year follow-up, 57 discography and 53 control subjects completed all interval surveillance evaluations. There were 16 lumbar surgeries in the discography group, compared with four in the control group. Medical visits, CT/MRI examinations, work loss, and prolonged back pain episodes were all more frequent in the discography group compared with control subjects. CONCLUSION: The disc puncture and pressurized injection performed during provocative discography can increase the risk of clinical disc problems in exposed patients.

The effect of pedicle screw redirection after lateral wall breach--a biomechanical study using human lumbar vertebrae.

BACKGROUND CONTEXT: Currently, pedicle screw segmental fixation of the spine is considered a standard of care for a number of conditions. Most surgeons employ a free-hand technique using various intraoperative modalities to improve pedicle screw accuracy. Despite continued improvements in technique, pedicle breach remains a frequent occurrence. Once a breach is detected intraoperatively, the most common corrective maneuver is to medially redirect the pedicle screw into the pedicle. To our knowledge, the biomechanical impact of medially redirecting a pedicle screw after a lateral pedicle breach has not been examined. PURPOSE: To compare the fixation strength of perfectly placed pedicle screws to the fixation strength of pedicle screws that were correctly placed after having been redirected (RD) following a lateral pedicle breach. STUDY DESIGN/SETTING: A biomechanical study using human lumbar vertebrae. METHODS: Ten fresh human lumbar vertebrae were isolated from five donors. Each vertebra was instrumented with a monoaxial pedicle screw into each pedicle using two different techniques. On one side, a perfect center-center (CC) screw path was created using direct visualization and fluoroscopy. A 6.0-mm-diameter cannulated tap and a pedicle probe were used to develop the pedicle for the 7.0-mm-diameter by 45-mm-long cannulated pedicle screw, which was placed using a digital torque driver. On the contralateral side, an intentional lateral pedicle wall breach was created at the pedicle-vertebral body junction using a guide wire, a 6.0-mm-diameter cannulated tap, and a pedicle probe. This path was then redirected into a CC position, developed, and instrumented with a 7.0-mm-diameter by 45-mm-long cannulated pedicle screw: the RD screw. For each pedicle screw, we assessed four outcome measures: maximal torque, seating torque, screw loosening, and post-loosening axial pullout. Screw loosening and axial pullout were assessed using an MTS machine. RESULTS: The biomechanical cost of a lateral pedicle breach and the requirement to redirect the pedicle screw are as follows: an overall drop of 28% (p<.002) in maximal insertion torque and 25% (p<.049) in seating torque, a drop of 25% (p<.040) in resistance to screw loosening, and a drop in axial pullout force of 11% (p<.047). CONCLUSIONS: Compared with a CC lumbar pedicle screw, an RD lumbar pedicle screw placed after a lateral wall breach is significantly weaker in terms of maximal insertional torque, seating torque, screw loosening force, and axial pullout strength. These significant decreases in biomechanical properties are clearly important when RD pedicle screws are placed at the cephalad or caudal end of a long construct. In this situation, augmentation of the RD screw is an option.

Pedicle screw accuracy and the ramifications of imperfect screw placement.

COMMENTARY ON: Oh HS, Kim JS, Lee SH, et al. Comparison between the accuracy of percutaneous and open pedicle screw fixations in lumbosacral fusion. Spine J 2013;13:1751-7 (in this issue). Costa F, Villa T, Anasetti F, et al. Primary stability of pedicle screws depends on the screw positioning and alignment. Spine J 2013;13:1934-9 (in this issue).

Functional outcome after percutaneous tendo-Achilles lengthening.

BACKGROUND: Percutaneous tendo-Achilles lengthening (PTAL) is a common procedure performed as an adjunct to other procedures that are used to treat a variety of foot and ankle disorders. Despite the widespread use of PTAL, the only literature to substantiate its efficacy comes from the treatment of forefoot ulceration in diabetics. The complications of the procedure include pain along the Achilles tendon, difficulty using stairs, weakness with toe-off, inadvertent complete tenotomy, and cosmetic appearance. We sought to investigate the functional outcomes specific to PTAL when performed in tandem with triple arthrodesis and subtalar fusion. MATERIALS AND METHODS: A retrospective review of 107 patients who underwent 117 procedures was performed. Outcomes were assessed by telephone interview using a standard questionnaire. The most common procedure in the study population was triple arthrodesis (91%). RESULTS: Fifty-eight percent of the patients reported moderate improvement in motion postoperatively, but 80% reported some degree of persistent stiffness. Despite 38% of patients reporting postoperative weakness, 66% and 61% stated that ascending and descending stairs, respectively, was easier. CONCLUSION: Overall, 81% of the study population had a positive opinion regarding their surgery. In this heterogeneous population, we showed modest improvement in Achilles tendon-related outcomes when PTAL was performed in tandem with other surgeries.

Combined subtalar and ankle arthritis.

Combined ankle and subtalar arthritis is a difficult problem for which there are varied solutions. Each solution has its advantages and disadvantages. Treatment must be specifically tailored to the patient's needs, comorbidities, and expectations. Because of the complicated nature of this condition and its treatment, complications are common and should be anticipated.