Andrew B. Boucher, Osama N. Kashlan, Matthew F. Gary and Daniel Refai
Siri Sahib Khalsa, Hyeun Sung Kim, Ravindra Singh and Osama Nezar Kashlan
Lumbar central stenosis can theoretically be decompressed with minimal bone removal via an endoscopic approach. Although multiple studies have demonstrated an adequate radiographic decompression, none has quantified the volume of bone removal after endoscopic decompression. The objective of this study was to quantify the 3D volume of bone removed from the lamina and facet joints during endoscopic decompression for lumbar central and lateral recess stenosis.
This retrospective study included adults with lumbar spinal stenosis who underwent endoscopic decompression of a single level or 2 noncontiguous lumbar levels. Central stenosis on MRI was graded preoperatively and postoperatively using the Schizas scale. A computer program was developed in MATLAB to semiautomatically perform a 3D volumetric analysis of preoperative and postoperative lumbar CT scans. The volumetric percentage of bone removed from the lamina and facet joints ipsilateral and contralateral to the side of approach was quantified.
Nineteen patients with 21 treated lumbar levels were included in the study. Preoperatively, the number of levels with Schizas stenosis grades B, C, and D were 5, 12, and 4, respectively. Stenosis grades improved postoperatively to grades A, B, C, and D for 17, 3, 1, and 0 levels, respectively. All levels improved by at least 1 stenosis grade. The volumetric percentage of laminar bone removed was 15.5% (95% CI 11.2%–19.8%, p < 0.001) from the ipsilateral lamina and 8.8% (95% CI 5.7%–11.8%, p < 0.001) from the contralateral lamina. The percentage of facet joint resection was 5.3% (95% CI 4.2%–6.4%, p < 0.001) and 4.3% (95% CI 2.2%–6.4%, p < 0.001) for the ipsilateral and contralateral facet joints, respectively. Average pain scores, as measured by the visual analog scale, improved from 7.9 preoperatively to 2.2 by 3–10 months postoperatively (p < 0.001).
Endoscopic lumbar decompression achieves improvement in the radiographic grade of lumbar central stenosis with minimal bone removal from the lamina and facet joints. Future prospective studies are needed to validate the findings of this study with more comprehensive clinical outcomes.
Osama N. Kashlan, D. Andrew Wilkinson, Hal Morgenstern, Siri S. Khalsa and Cormac O. Maher
Thickened or fatty filum terminale is an occult lesion that can cause tethered cord syndrome requiring surgical untethering. This study’s objectives were to estimate the incidence of tethered fibrofatty filum terminale (TFFT) in a large insured pediatric population, identify predictors of surgery among those TFFT patients, and assess a diagnostic algorithm.
TFFT was defined according to the ICD-9-CM code for cord tethering (742.59), after excluding codes for diastematomyelia, lipomyelomeningocele, terminal myelocystocele, meningocele, and myelomeningocele. Utilizing the Optum Insight database for 2001–2014, the authors identified pediatric patients (< 21 years) in the US who were diagnosed with a tethered cord and estimated the TFFT incidence rates in that source population and the surgical untethering probability among TFFT patients over the 14-year period. Logistic regression was used to estimate the effects (adjusted OR and 95% CI) of age at diagnosis, sex, Charlson Comorbidity Index (CCI) score, diagnosis of Chiari malformation type I, diagnosis of syrinx, and the probability of surgery by US census region. Lastly, to evaluate their algorithm for identifying TFFT from ICD-9 codes, the authors estimated its positive predictive value (PPV) among 50 children who were diagnosed at their institution and met the ICD-9-CM criteria.
There were 3218 diagnoses of TFFT, with 482 of these pediatric patients undergoing tethered cord release during the study period. The estimated incidence rate was 12.0 per 100,000/year (95% CI 11.6–12.4 per 100,000/year). The incidence rate was slightly higher in females than in males (12.7 vs 11.4 per 100,000/year). The probability of surgery in the total pediatric TFFT population was 15.0% (95% CI 13.8%–16.2%) and was greater in children with a syrinx (OR 2.2, 95% CI 1.6–3.0), children 7–11 years of age at diagnosis versus < 1 year (OR 1.5, 95% CI 1.1–2.0), CCI score ≥ 3 versus 0 (OR 2.3, 95% CI 1.4–3.8), and residents of the Western vs Northeastern US (OR 2.3, 95% CI 1.6–3.5). In the authors’ own institution’s database, the PPV of TFFT was 35/50 (70.0%, 95% CI 57.3%–82.7%) for identifying tethered cord due to fibrofatty filum terminale among childhood positives.
Patients with comorbidities or an associated syrinx showed a higher risk of untethering procedures for TFFT. Also, surgery was appreciably more frequent in the Western US. These findings signify the need for a collaborative prospective cohort study of long-term outcomes for TFFT patients with and without surgery to determine which patients should have surgery.
Osama N. Kashlan, Thomas J. Wilson, Neeraj Chaudhary, Joseph J. Gemmete, William R. Stetler Jr., N. Reed Dunnick, B. Gregory Thompson and Aditya S. Pandey
As medical costs continue to rise during a time of increasing medical resource utilization, both hospitals and physicians must attempt to limit superfluous health care expenses. Neurointerventional treatment has been shown to be costly, but it is often the best treatment available for certain neuropathologies. The authors studied the effects of 3 policy changes designed to limit the costs of performing neurointerventional procedures at the University of Michigan.
The authors retrospectively analyzed the costs of performing neurointerventional procedures during the 6-month periods before and after the implementation of 3 cost-saving policies: 1) the use of an alternative, more economical contrast agent, 2) standardization of coil prices through negotiation with industry representatives to receive economies of scale, and 3) institution of a feedback method to show practitioners the costs of unused products per patient procedure. The costs during the 6-month time intervals before and after implementation were also compared with costs during the most recent 6-month time period.
The policy requiring use of a more economical contrast agent led to a decrease in the cost of contrast usage of $42.79 per procedure for the first 6 months after implementation, and $137.09 per procedure for the most current 6-month period, resulting in an estimated total savings of $62,924.31 for the most recent 6-month period. The standardized coil pricing system led to savings of $159.21 per coil after the policy change, and $188.07 per coil in the most recent 6-month period. This yielded total estimated savings of $76,732.56 during the most recent 6-month period. The feedback system for unused items decreased the cost of wasted products by approximately $44.36 per procedure in the 6 months directly after the policy change and by $48.20 per procedure in the most recent 6-month period, leading to total estimated savings of $22,123.80 during the most recent 6-month period. According to extrapolation over a 1-year period, the 3 policy changes decreased costs by an estimated $323,561.34.
Simple cost-saving policies can lead to substantial reductions in costs of neurointerventional procedures while maintaining high levels of quality and growth of services.