Neil N. Patel

Reoperation Rates Following Single-Level Lumbar Discectomy.

Study Design. Retrospective analysis of national insurance billing database. Objective. To examine trends in reoperation after single-level lumbar discectomy. Summary of Background Data. Lumbar discectomy is the most commonly performed procedure for treatment of radiculopathy caused by disc herniation. Randomized clinical trials have demonstrated the advantage of discectomy over nonsurgical treatment options, allowing for a more rapid reduction in symptoms. However, population-level data regarding reoperation after single level discectomy is limited. Methods. Data were collected using the commercially available PearlDiver software for patients billed with the Current Procedural Terminology code for our index procedure, hemilaminotomy and removal of disc material, between January 2007 and September 2014. The index group was then followed for up to 4 years for recurrent lumbar surgery, including spinal fusion, laminectomy, and additional discectomy. Results. Analysis of data obtained from 13,654 patient records revealed a rate of additional lumbar surgeries after single-level discectomy of 3.95% (539/13654) within 3 months and 12.2% (766/6274) within 4 years of the index procedure. Lumbar spinal fusion was performed on 5.9% (370/6274) of patients within 4 years. Patients who received a re-exploration discectomy within 2 years of the index procedure went on to receive lumbar fusion at a rate of 38.4% (48/125) within the 4 years after the re-exploration discectomy. The average additional cost of lumbar reoperation, as measured by insurance reimbursement, was approximately

The Clinical Correlations between Diabetes, Cigarette Smoking and Obesity on Intervertebral Degenerative Disc Disease of the Lumbar Spine

11,161 per-patient per year. Conclusion. We report an overall 4-year reoperation rate of 12.2% after single-level discectomy. In addition, we report a rate of progression to lumbar fusion following re-exploration discectomy of 38.4% within 4 years of reoperation. Further studies are needed regarding the best treatment algorithm in patients with reherniation or iatrogenic instability after lumbar discectomy. This study should enhance the shared decision making process by providing surgeons and patients with valuable data regarding the frequency and nature of reoperations after discectomy. Level of Evidence: 3

Postoperative complications in patients undergoing minimally invasive sacroiliac fusion

Study Design Retrospective analysis of a nationwide private insurance database. Chi-square analysis and linear regression models were utilized for outcome measures. Purpose The purpose of this study was to investigate any relationship between lumbar degenerative disc disease, diabetes, obesity and smoking tobacco. Overview of Literature Diabetes, obesity, and smoking tobacco are comorbid conditions known to individually have effect on degenerative disc disease. Most studies have only been on a small populous scale. No study has yet to investigate the combination of these conditions within a large patient cohort nor have they reviewed the combination of these conditions on degenerative disc disease. Methods A retrospective analysis of insurance billing codes within the nationwide Humana insurance database was performed, using PearlDiver software (PearlDiver, Inc., Fort Wayne, IN, USA), to identify trends among patients diagnosed with lumbar disc degenerative disease with and without the associated comorbidities of obesity, diabetes, and/or smoking tobacco. Patients billed for a comorbidity diagnosis on the same patient record as the lumbar disc degenerative disease diagnosis were compared over time to patients billed for lumbar disc degenerative disease without a comorbidity. There were no sources of funding for this manuscript and no conflicts of interest. Results The total number and prevalence of patients (per 10,000) within the database diagnosed with lumbar disc degenerative disease increased by 241.4% and 130.3%, respectively. The subsets of patients within this population who were concurrently diagnosed with either obesity, diabetes, tobacco use, or a combination thereof, was significantly higher than patients diagnosed with lumbar disc degenerative disease alone (p <0.05 for all). The number of patients diagnosed with lumbar disc degenerative disease and smoking rose significantly more than patients diagnosed with lumbar disc degenerative disease and either diabetes or obesity (p <0.05). The number of patients diagnosed with lumbar disc degenerative disease, smoking and obesity rose significantly more than the number of patients diagnosed with lumbar disc degenerative disease and any other comorbidity alone or combination of comorbidities (p <0.05). Conclusions Diabetes, obesity and cigarette smoking each are significantly associated with an increased diagnosis of lumbar degenerative disc disease. The combination of smoking and obesity had a synergistic effect on increased rates of lumbar degenerative disc disease. Patient education and preventative care is a vital goal in prevention of degenerative disc disease within the general population.

Complications associated with the Dynesys dynamic stabilization system: a comprehensive review of the literature

BACKGROUND CONTEXT Minimally invasive sacroiliac (SI) joint fusion has become increasingly relevant in recent years as a treatment for SI joint pathology. Previous studies have found minimally invasive SI fusion to be an effective and safe treatment option for chronic SI joint pain. However, these studies have been primarily single-center, case-based, or manufacturer-sponsored investigations, and as such their findings are limited to their sample populations. PURPOSE The aim of this study was to investigate the safety of minimally invasive SI fusion using a large nationwide sample group to more accurately identify complication rates of this increasingly popular procedure. STUDY DESIGN/SETTING This is a retrospective database study. PATIENT SAMPLE The sample includes patients within the orthopedic subset of Humana database who underwent minimally invasive SI fusion between 2007 and 2014. OUTCOME MEASURES Complications and novel lumbar and nerve pathology were the outcome measures. METHODS Patients undergoing minimally invasive SI fusion from 2007 to 2014 were identified using the Pearl Diver patient record database (Pearl Diver Technologies, West Conshohocken, PA, USA) from the nationwide private insurance provider Humana Inc. This approach provided access to records of over 18 million patients in every major geographic region of the country. Using the ICD-9 diagnosis codes (International Classification of Diseases 9th edition), data from patient records were analyzed to reveal incidence of postoperative infection, pain, osteomyelitis, joint derangement, urinary tract infection, and novel lumbar and nervous system pathology. RESULTS Four hundred sixty-nine patients (305 female; 164 male) within the Humana insurance database received minimally invasive SI fusion between 2007 and 2014. Data from these patients showed a substantial increase in the use of the procedure over this 7-year period. Among these patients, an overall complication rate of 13.2% (n=62) was seen at 90 days postoperatively and 16.4% (n=77) at 6 months. The number of patients receiving a first time diagnosis of lumbar pathology following minimally invasive SI fusion in the sample population was also analyzed. The incidence of novel lumbar pathology in this population was 3.6% (n=17) at 90 days postoperatively and 5.3% (n=25) at 6 months. Men experienced diagnoses of novel lumbar pathology at higher rates than women within both 90 days (men=6.7%; women≤3.3%) and 6 months (men=9.1%; women≤3.3%) of the procedure (p<.01). CONCLUSIONS The results of this study show that minimally invasive SI joint fusion could possibly carry higher risks of complications than previously stated. These findings are useful for physicians and patients when considering treatment for chronic SI joint pain.

Bisphosphonate's and Intermittent Parathyroid Hormone's Effect on Human Spinal Fusion: A Systematic Review of the Literature

The Dynesys dynamic stabilization system is an alternative to rigid instrumentation and fusion for the treatment of lumbar degenerative disease. Although many outcomes studies have shown good results, currently lacking is a comprehensive report on complications associated with this system, especially in terms of how it compares with reported complication rates of fusion. For the present study, the authors reviewed the literature to find all studies involving the Dynesys dynamic stabilization system that reported complications or adverse events. Twenty-one studies were included for a total of 1166 patients with a mean age of 55.5 years (range 39-71 years) and a mean follow-up period of 33.7 months (range 12.0-81.6 months). Analysis of these studies demonstrated a surgical-site infection rate of 4.3%, pedicle screw loosening rate of 11.7%, pedicle screw fracture rate of 1.6%, and adjacent-segment disease (ASD) rate of 7.0%. Of studies reporting revision surgeries, 11.3% of patients underwent a reoperation. Of patients who developed ASD, 40.6% underwent a reoperation for treatment. The Dynesys dynamic stabilization system appears to have a fairly similar complication-rate profile compared with published literature on lumbar fusion, and is associated with a slightly lower incidence of ASD.

Semitendinosus Graft for Interspinous Ligament Reinforcement in Adult Spinal Deformity.

There has been a conscious effort to address osteoporosis in the aging population. As bisphosphonate and intermittent parathyroid hormone (PTH) therapy become more widely prescribed to treat osteoporosis, it is important to understand their effects on other physiologic processes, particularly the impact on spinal fusion. Despite early animal model studies and more recent clinical studies, the impact of these medications on spinal fusion is not fully understood. Previous animal studies suggest that bisphosphonate therapy resulted in inhibition of fusion mass with impeded maturity and an unknown effect on biomechanical strength. Prior animal studies demonstrate an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. The purpose of this study was to determine if bisphosphonates and intermittent PTH treatment have impact on human spinal fusion. A systematic review of the literature published between 1980 and 2015 was conducted using major electronic databases. Studies reporting outcomes of human subjects undergoing 1, 2, or 3-level spinal fusion while receiving bisphosphonates and/or intermittent PTH treatment were included. The results of relevant human studies were analyzed for consensus on the effects of these medications in regards to spinal fusion. There were nine human studies evaluating the impact of these medications on spinal fusion. Improved fusion rates were noted in patients receiving bisphosphonates compared to control groups, and greater fusion rates in patients receiving PTH compared to control groups. Prior studies involving animal models found an improved fusion rate and fusion mass microstructure with the use of intermittent PTH. No significant complications were demonstrated in any study included in the analysis. Bisphosphonate use in humans may not be a deterrent to spinal fusion. Intermittent parathyroid use has shown early promise to increase fusion mass in both animal and human studies but further studies are needed to support routine use.

The use of a novel perfusion-based cadaveric simulation model with cerebrospinal fluid reconstitution comparing dural repair techniques: a pilot study

Proximal junctional kyphosis is an increasingly recognized complication following long-segment posterior spinal fusion for adult spinal deformity. The authors describe a novel technique for interspinous ligament reinforcement at the proximal adjacent levels using a cadaveric semitendinosus tendon graft secured with an Ethibond No. 2 double filament (Ethicon, Somerville, New Jersey) via the Krackow suture weave. A retrospective review identified 4 patients who had received this graft. No proximal junctional kyphosis was seen at a mean short-term follow-up of 5.5 months. Interspinous ligament reinforcement at the proximal adjacent level with a cadaveric semitendinosus tendon graft is a feasible strategy for preventing proximal junctional kyphosis. [Orthopedics. 2017; 40(1):e206-e210.].

Analysis of Lumbar Foramina Size Change in Patients with Lumbar Spondylolisthesis using Kinetic Magnetic Resonance Imaging

BACKGROUND CONTEXT Watertight dural repair is crucial for both incidental durotomy and closure after intradural surgery. PURPOSE The study aimed to describe a perfusion-based cadaveric simulation model with cerebrospinal fluid (CSF) reconstitution and to compare spine dural repair techniques. STUDY DESIGN/SETTING The study is set in a fresh tissue dissection laboratory. SAMPLE SIZE The sample includes eight fresh human cadavers. OUTCOME MEASURES A watertight closure was achieved when pressurized saline up to 40 mm Hg did not cause further CSF leakage beyond the suture lines. METHODS Fresh human cadaveric specimens underwent cannulation of the intradural cervical spine for intrathecal reconstitution of the CSF system. The cervicothoracic dura was then exposed from C7-T12 via laminectomy. The entire dura was then opened in six cadavers (ALLSPINE) and closed with 6-0 Prolene (n=3) or 4-0 Nurolon (n=3), and pressurized with saline via a perfusion system to 60 mm Hg to check for leakage. In two cadavers (INCISION), six separate 2-cm incisions were made and closed with either 6-0 Prolene or 4-0 Nurolon, and then pressurized. A hydrogel sealant was then added and the closure was pressurized again to check for further leakage. RESULTS Spinal laminectomy with repair of intentional durotomy was successfully performed in eight cadavers. The operative microscope was used in all cases, and the model provided a realistic experience of spinal durotomy repair. For ALLSPINE cadavers (mean: 240 mm dura/cadaver repaired), the mean pressure threshold for CSF leakage was observed at 66.7 (±2.9) mm Hg in the 6-0 Prolene group and at 43.3 (±14.4) mm Hg in the 4-0 Nurolon group (p>.05). For INCISION cadavers, the mean pressure threshold for CSF leakage without hydrogel sealant was significantly higher in 6-0 Prolene group than in the 4-0 Nurolon group (6-0 Prolene: 80.0±4.5 mm Hg vs. 4-0 Nurolon: 32.5±2.7 mm Hg; p<.01). The mean pressure threshold for CSF leakage with the hydrogel sealants was not significantly different (6-0 Prolene: 100.0±0.0 mm Hg vs. 4-0 Nurolon: 70.0±33.1 mm Hg). The use of a hydrogel sealant significantly increased the pressure thresholds for possible CSF leakage in both the 6-0 Prolene group (p=.01) and the 4-0 Nurolon group (p<.01) when compared with mean pressures without the hydrogel sealant. CONCLUSIONS We described the feasibility of using a novel cadaveric model for both the study and training of watertight dural closure techniques. 6-0 Prolene was observed to be superior to 4-0 Nurolon for watertight dural closure without a hydrogel sealant. The use of a hydrogel sealant significantly improved watertight dural closures for both 6-0 Prolene and 4-0 Nurolon groups in the cadaveric model.

Reoperation Rates Following Single-Level Discectomy

Introduction The pathology of lumbar spondylolisthesis contributes to lumbar instability and significant clinical symptoms. However, the effect on intervertebral foraminal area (FA) during motion change is not well understood. Material and Methods In this study we used 107 patients diagnosed with single or multiple level lumbar spondylolisthesis at L3–L4, L4–L5 or L5–S1. All patients were initially divided into two groups: group A (sliding percentage 0–3%) and group B (sliding percentage ≥4%). Sliding percentage and FA size in neutral, flexion and extension were measured using kMRI. The FA change in different sliding groups at L5-S1 level was further analyzed. Results The number of patients in the group A (sliding percentage 1–3%) was 68 at L3–4, 38 at L4–5 and 32 at L5-S1 spine levels. The number of patients in the group B (sliding percentage ≥4%) was the following: 39 at L3–L4, 69 at L4–L5 and 75 at L5–S1. The mean FA in both groups changed with different spine positions. When considering all levels, the average FA increased ~17% from neutral to flexion and decreased ~21% from neutral to extension. Similarly, there was a significant difference in FA in flexion at L5-S1 (p < 0.004) between the groups. For L5/S1 patients, 104 patients were divided into three sub-groups according to the sliding percentage (group I (0–9%), group II (10–19%) and group III (20–29%)). The FA was significantly increased in the flexion position and decreased in the extension position in all three groups. In group III FA size was significantly decreased from neutral to flexion when compared with Group I (p < 0.022). The FA size was significantly increased from neutral to extension when group III was compared with groups I and II (p < 0.000 and p < 0.017, respectively). Conclusion Our kMRI study revealed position-dependent changes of the intervertebral foramen. In patients with severe sagittal subluxation the change in FA from neutral to extension position demonstrated the largest decrease. This change may also correlate with changes in neuroforaminal stenosis and nerve root compression and its associated symptoms and should be taken in consideration when choosing the treatment option.

Reoperation Rates following Single-Level Lumbar Discectomy

Introduction Lumbar discectomy is the most commonly performed procedure for treatment of radiculopathy due to lumbar disc herniation. Randomized trials have demonstrated the advantage of surgical removal of herniated disc material over non-surgical treatment options, allowing for a more rapid reduction in symptoms and return of function. Many small-size studies suggest that long-term outcomes for patients treated with discectomy and non-operative management are similar. Additionally, treatment of recurrent lumbar disc herniation is not standardized. Population-level data regarding reoperation following single level hemilaminotomy and discectomy is limited. Material and Methods Data was collected and analyzed for 13,654 patients undergoing single-level lumbar discectomy between January 2007 and December 2010 using the commercially available PearlDiver software (PearlDiver, Inc., Fort Wayne, IN, USA). The nationwide Humana private insurance database was queried for patients billed with the Current Procedural Terminology (CPT) code for our index procedure, hemilaminotomy and removal of disc material (CPT-63030). Patients receiving concurrent lumbar surgeries were excluded from the index group. The index group was then followed in retrospective cohorts for 3 months, 6 months, 1 year, 2 years, and 4 years for recurrent lumbar surgery, including spinal fusion, laminectomy, and additional discectomy. Results Patients received additional lumbar surgeries following single-level discectomy at a rate of 3.95% (539/13654) within 3 months and 12.2% (766/6274) within 4 years of the index procedure. Lumbar spinal fusion was performed on 5.90% (370/6274) of patients within 4 years, with interbody fusion in 75.4% (279/370) of cases and multi-level fusion in 47.0% (174/370) of cases. Reoperation for re-exploration discectomy at the same level as the index procedure with no subsequent surgeries occurred in 2.71% (170/6274) of patients followed out to 4 years. Patients who received a re-exploration discectomy at the same intervertebral level within 2 years of the index procedure went on to receive lumbar fusion at a rate of 38.4% (48/125) within the 4 years following the re-exploration discectomy. Conclusion Data in our study demonstrated a reoperation rate of 12.2% after single level discectomy, a routinely performed procedure for the treatment of symptomatic lumbar disk herniation. Moreover, we show that the rate of progression to lumbar fusion after a re-exploration discectomy was 38.4% within 4 years of reoperation. These data should help surgeons in their operative decision-making and counseling recommendations to patients. To our knowledge, this is the largest population study delineating reoperation rates across the US after single-level lumbar discectomy. Further studies are needed regarding the best treatment algorithm in patients with re-herniation or iatrogenic instability following lumbar discectomy.