Predicting the Need for Surgery in Patients with Lumbar Disc Herniation: A New Internally Validated Scoring System.

STUDY DESIGN: Prospective study. PURPOSE: To propose a scoring system for predicting the need for surgery in patients with lumbar disc herniation (LDH). OVERVIEW OF LITERATURE: The indications for surgery in patients with LDH are well established. However, the exact timing of surgery is not. According to surgeons, patients with failed conservative treatment who underwent delayed surgery, often after 6 months postsymptom initiation, have poor functional recovery and outcome. METHODS: The current study included patients with symptomatic LDH. Patients with an indication for emergent surgery such as profound or progressive motor deficit, cauda equina syndrome, and diagnoses other than single-level LDH were excluded from the analysis. All patients followed a conservative treatment regimen (a combination of physical therapy, pain medications, and/or spinal epidural steroid injections). Surgery was indicated for patients who continuously experienced pain despite maximal conservative therapy. RESULTS: In total, 134 patients met the inclusion and exclusion criteria. Among them, 108 (80.6%) responded to conservative management, and 26 (19.4%) underwent unilateral laminotomy and microdiscectomy. The symptom duration, disc degeneration grade on magnetic resonance imaging (Pfirrmann disc grade), herniated disc location and type, fragment size, and thecal sac diameter significantly differed between patients who responded to conservative treatment and those requiring surgery. The area under the receiver operating characteristic curve of the scoring system based on the anteroposterior size of the herniated disc fragment and herniated disc location and type was 0.81. CONCLUSIONS: A scoring system based on herniated disc/fragment size, location, and type can be applied to predict the need for surgery in patients with LDH. In the future, this tool can be used to prevent unnecessarily prolonged conservative management (>4-8 weeks).

Effect of Body Mass Index on Fusion Outcome After Short-Segment Posterior Lumbar Fusion.

OBJECTIVE: Obesity is a growing epidemic in the United States. While many adverse effects of obesity on surgical outcome are well studied, a direct correlation among obesity, pseudarthrosis, and adjacent segment pathology is not well defined. In this study we aimed to identify the effect of body mass index (BMI) on pseudarthrosis, adjacent segment pathology (ASP), and reoperation after short-segment (1-3 levels) open posterior lumbar fusion (PLF). METHODS: This is a retrospective study of patients with degenerative spine pathologies who underwent 1-, 2-, or 3-level PLF surgery between 2010 and 2020. The relevant medical and imaging records were reviewed, and the following variables were recorded: age, gender, BMI, smoking status, surgical details, follow-up length, need for reoperation, indication for reoperation (pseudarthrosis or occurrence of ASP). RESULTS: We included363 patients in our study. Twenty-five patients (6.9%) developed pseudarthrosis, 109 (30%) developed ASP, and 104 patients (28.7%) underwent reoperation for either of these reasons. BMI was significantly less in those who developed pseudarthrosis compared with those who did not (28.6 ± 5.5 vs. 31.2 ± 6.2, respectively; P = 0.04). BMI was not significantly different in those who developed ASP or underwent reoperation compared with those who did not (P = 0.06 and 0.08, respectively). Multivariate regression analysis showed none of the variables in the model (age, gender, tobacco use, BMI, and its classes) significantly predicted pseudarthrosis, ASP, or reoperation (P > 0.1 for all variables). CONCLUSIONS: Obese patients undergoing short-segment open PLF have comparable results in terms of pseudarthrosis, ASP, and reoperation.

Effect of Obesity on Surgical Outcomes of Lumbar Microdiscectomy: A Retrospective Analysis of 525 Patients.

INTRODUCTION: Obesity has been implicated in higher rates of intra-operative complications, as well as increased risk for recurrent herniation and re-operation following lumbar microdiscectomy (LMD). However, the current literature is still controversial about whether obesity adversely affects surgical outcomes, especially a higher re-operation rate. In this study, we have compared surgical outcomes such as recurrence of symptoms, recurrence of disc herniation, and re-operation rates in obese and non-obese patients undergoing one segment LMD. METHODS: A retrospective review was conducted on patients undergoing single-level LMD between 2010-2020 at an academic institution. Exclusion criteria included prior lumbar surgery. Outcomes assessed included the presence of persistent radicular pain, imaging evidence of recurrent herniation, and the need for re-operation due to recurrent herniation. RESULTS: A total of 525 patients were included in the study. The mean±SD body mass index (BMI) was 31.2±6.6 (range 16.2-70.0). The mean follow-up was 273.8±445.2 days (range 14-2494). Reherniation occurred in 84 patients (16.0%), and 69 (13.1%) underwent re-operation due to persistent recurrent symptoms. Neither reherniation nor re-operation was significantly associated with BMI (p = 0.47 and 0.95, respectively). Probit analysis did not show any significant association between BMI and the need for re-operation following LMD. CONCLUSION: Obese and non-obese patients experienced similar surgical outcomes. Our results showed that BMI did not adversely affect reherniation or re-operation rate following LMD. If clinically indicated, LMD can be performed in obese patients with disc herniation without a significantly higher re-operation rate.

Does the Number of Interbody Devices Affect the Fusion Outcome in Short-Segment Posterior Lumbar Fusion?

INTRODUCTION: Interbody devices (IBDs) have been shown to improve outcomes when used in posterior lumbar fusion (PLF) surgery; however,the exact extent of their clinical benefit remains a current topic of interest. Our primary objective in this study was to identify whether the use of an IBD at every level of fusion construct would affect fusion outcomes such as adjacent segment pathology (ASP) and pseudarthrosis after one- to three-level PLF surgery. METHODS: This was a single-institution retrospective study. We studied the association of factors such as smoking status, BMI, gender, age, and number of IBDs on the development of ASP and pseudarthrosis. To study the effect of independent variables on ASP and pseudoarthrosis, univariate and multivariate regression analyses were used. RESULTS: The study included 2,061 patients with a history of posterior lumbar fusion who were identified and reviewed. Among these, 363 patients met our inclusion criteria; 247 patients had a minimum follow-up of six months and were finally included in the study. The median follow-up was 30 months. Among the 247 patients, 105 (42.5%) and 24 (9.7%) experienced ASP and pseudarthrosis, respectively. Gender and use of IBD significantly affected the presence of pseudarthrosis (with a higher rate in males and those without any IBDs). Gender, age, BMI, and use of IBDs did not affect ASP. Moreover, using an IBD at each fused level reduced the pseudarthrosis rate significantly compared to when IBDs were not used at all levels (7.3% vs. 27.6%, p <0.001), while there was no significant difference in the rate of ASP (43.6% vs. 34.5%, p = 0.35). CONCLUSIONS: In patients undergoing one- to three-level PLF surgery, the use of an IBD at all levels of the fusion construct significantly reduces the rate of pseudarthrosis. There was no significant correlation between the rates of ASP. Studies with a larger sample size and a longer follow-up time are suggested to validate our results for pseudoarthrosis and ASP. Our results suggest the use of an IBD per fusion level in short-segment PLF surgeries.

The Effect of Interbody Cage Parameters on the Rate of Subsidence in Single-Level Anterior Cervical Discectomy and Fusion (ACDF): A Retrospective Analysis of 98 Patients.

INTRODUCTION: Subsidence is a relatively common consequence after anterior cervical discectomy and fusion (ACDF) surgery. This study aimed to identify the effect of radiological and non-radiological risk factors on subsidence after a single-level ACDF surgery with cage and plate. METHODS: This is a retrospective cohort study of patients who underwent ACDF for radiculopathy or myelopathy at an academic center, University of Kentucky Albert Chandler Hospital, Lexington, Kentucky, United States, between January 2010 and January 2020. Subsidence was defined as the sinking of the interbody cage into the vertebral body at either the superior end plate (SEP) or inferior end plate (IEP) at the ACDF level and was measured manually on lateral standing x-ray. The numerical amount of subsidence was measured in millimeters as the sum of subsidence in the SEP and IEP and was further categorized into subsidence2 and subsidence3 (i.e., presence of subsidence > 2 mm and subsidence > 3 mm, respectively). Multivariate regression analysis was used to assess the effect of variables such as age, gender, body mass index (BMI), tobacco use, follow-up length, cage type, anterior cage height, posterior cage height, anterior cage height ratio, posterior cage height ratio, cage position, cage-end plate interface and cervical alignment on outcomes such as subsidence, subsidence2, and subsidence3. RESULTS: A total of 98 patients were included, of which 46 (47.1%) were male. The mean age of the population was 47.6±8.4 years. Fifty-one patients (52%) experienced subsidence more than 3 mm. Anterior disc height ratio (ADHR) was calculated by dividing the anterior cage height by the anterior disc height (pmADH). The posterior disc height ratio (PDHR) was calculated by dividing the posterior cage height by the posterior disc height (pmPDH). There was no significant correlation between ADHR and PDHR with subsidence, (p=0.93 and 0.56, respectively). Gender, age, BMI, and smoking status did not affect subsidence either. Cage type significantly affected subsidence with a higher subsidence rate in VG2 cages compared to Bengal cages (p=0.05). CONCLUSION:  This study showed that in patients undergoing single-level ACDF with cage and plate, cage size and in particular cage height (if adjusted for individual patients) did not affect subsidence. Other factors such as cage-endplate interface, cage depth in interbody space, and cervical alignment did not significantly affect subsidence either. This might be attributable to the use of an anterior plating system that conducts the force and reduces the stress on the graft-bone interface.

Measurement of instant flow reserve to quantify functional flow limitation across stenosis in intracranial atherosclerotic disease.

Angiographic stenosis may not be an accurate reflection of physiological flow limitation. Measurement of instant flow reserve (IFR) to quantify functional flow limitation across stenosis may be valuable in identifying lesions causing significant flow limitation. A case of left middle cerebral artery atherosclerotic disease is presented. Because medical therapy had failed, endovascular revascularization was chosen. In this video 1, IFR measurement to guide submaximal balloon angioplasty with a 1.5×9 mm non-compliant Mini-Trek balloon (Abbott) is demonstrated. Pressure gradient across the middle cerebral artery-M1 stenosis was measured with a Volcano pressure wire (Philips) before and after submaximal balloon angioplasty. An excellent radiographic result and flow improvement into the severely stenosed segment were achieved, with an IFR increase from 0.23 to 0.89. The degree of corresponding stenosis changed from 85% to 30%. No periprocedural complication was observed. IFR can help to identify lesions requiring treatment in select patients and prevent the tendency to overtreat a lesion that is not physiologically significant.