A Portable Shoulder-Mounted Camera System for Surgical Education in Spine Surgery.

The past several years have demonstrated an increased recognition of operative videos as an important adjunct for resident education. Currently lacking, however, are effective methods to record video for the purposes of illustrating the techniques of minimally invasive (MIS) and complex spine surgery. We describe here our experiences developing and using a shoulder-mounted camera system for recording surgical video. Our requirements for an effective camera system included wireless portability to allow for movement around the operating room, camera mount location for comfort and loupes/headlight usage, battery life for long operative days, and sterile control of on/off recording. With this in mind, we created a shoulder-mounted camera system utilizing a GoPro™ HERO3+, its Smart Remote (GoPro, Inc., San Mateo, California), a high-capacity external battery pack, and a commercially available shoulder-mount harness. This shoulder-mounted system was more comfortable to wear for long periods of time in comparison to existing head-mounted and loupe-mounted systems. Without requiring any wired connections, the surgeon was free to move around the room as needed. Over the past several years, we have recorded numerous MIS and complex spine surgeries for the purposes of surgical video creation for resident education. Surgical videos serve as a platform to distribute important operative nuances in rich multimedia. Effective and practical camera system setups are needed to encourage the continued creation of videos to illustrate the surgical maneuvers in minimally invasive and complex spinal surgery. We describe here a novel portable shoulder-mounted camera system setup specifically designed to be worn and used for long periods of time in the operating room.

S-1 and S-2-alar-iliac screw fixation via intraoperative navigation.

Adult deformity patients often require fixation to the sacrum and pelvis for construct stability and improved fusion rates. Although certain sacropelvic fixation techniques can be challenging, the availability of intraoperative navigation has made many of these techniques more feasible. In this video case presentation, the authors demonstrate the techniques of S-1 bicortical screw and S-2-alar-iliac screw fixation under intraoperative navigation in a 67-year-old female. This instrumentation placement was part of an overall T-10-pelvis construct for the correction of adult spinal deformity. The video can be found here: https://youtu.be/3HZo-80jQr8 .

Minimally invasive L5-S1 oblique lumbar interbody fusion with anterior plate.

Lumbar interbody fusion is an important technique for the treatment of degenerative disc disease and degenerative scoliosis. The oblique lumbar interbody fusion (OLIF) establishes a minimally invasive retroperitoneal exposure anterior to the psoas and lumbar plexus. In this video case presentation, the authors demonstrate the techniques of the OLIF at L5-S1 performed on a 69-year-old female with degenerative scoliosis as one component of an overall strategy for her deformity correction. The video can be found here: https://youtu.be/VMUYWKLAl0g .

Complications associated with the Dynesys dynamic stabilization system: a comprehensive 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.

Acute Tetraplegia after Posterior Cervical Laminectomy for Chronic Myelopathy.

Spinal cord injury (SCI) during revision surgery for persistent multilevel cervical myelopathy (MCM) after an initial anterior procedure is rare. However, the pathophysiology of MCM, even prior to surgery, is a risk-factor for neurological deterioration due to the development of a "sick cord", which reflects pathological changes in the spinal cord that lower the threshold for injury. We report a case of persistent MCM despite a three-level ACDF and corpectomy who developed an incomplete C6 tetraplegia during revision cervical laminectomy and posterior instrumentation. Intraoperative neuromonitoring signal-changes occurred in the absence of mechanical trauma. Postoperative MRI of the cervical spine demonstrated increased T2 hyperintensity and cord expansion at C3 and C4 compared to the pre-laminectomy MRI. The patient has not made improvements in her neurological status at 13 months postoperatively. The pathophysiology of MCM is discussed in addition to perioperative imaging, neuromonitoring, and use of steroids.

Minimally Invasive Lateral Interbody Fusion in the Treatment of Scoliosis Associated with Myelomeningocele.

INTRODUCTION: Surgical correction of spinal deformity in myelomeningocele is associated with high rates of pseudarthrosis and implant failure. The anterior fusion is traditionally a wide exposure from the thorax to the sacrum. We report minimally invasive lateral interbody fusion (MILIF) to address the issue of fusion between vertebrae with marginal posterior elements while minimizing the morbidity of an open approach. MATERIALS AND METHODS: We performed a single-center, retrospective review of patients with myelomeningocele and severe scoliosis who underwent posterior spinal fusion (PSF) and staged MILIF for anterior fusion of the thoracolumbar/lumbar spine. We identified four patients with high risk of curve progression who met the following inclusion criteria: diagnosis of myelomeningocele, severe scoliosis (Cobb angle>70°), PSF using greater than 80% pedicle screws, age greater than 10 years at time of surgery, and a minimum follow-up of two years. Radiographic, clinical, and complication data were reviewed. RESULTS: All four patients achieved fusion (100%). The average age at index surgery was 12.8 years (range, 11-16) and follow-up was 3.2 years (range, 2-4.9). The average preoperative coronal Cobb angle measured 111° (range, 74-140°). The average postoperative Cobb angle at follow-up measured 37° (range, 23-42°). The MILIF procedure was performed an average of six months after the index procedure. After anterior fusion, all patients spent one day in the pediatric ICU and an average of 5.5 days in the hospital (range, 4-7). One patient (25%) developed a postoperative wound infection after PSF which required irrigation and debridement in the operating room. CONCLUSION: MILIF as an adjunct to posterior spinal fusion for severe scoliosis associated with myelomeningocele may provide acceptable fusion rates, curve correction, maintenance of correction at mid-term follow-up, and be associated with less morbidity than the traditional anterior approach.

How should unmatched orthopaedic surgery applicants proceed?

BACKGROUND: Obtaining an orthopaedic surgery residency is competitive. Advisors must understand what factors may help unmatched candidates reapply successfully. QUESTIONS/PURPOSES: We determined (1) the attitude of leaders of orthopaedic surgery residency programs toward interviewing unmatched students; (2) whether a surgical internship or a research year is preferred in considering reapplicants; (3) the importance of United States Medical Licensing Examination (USMLE) scores, recommendations, and Alpha Omega Alpha (AOA) membership; and (4) whether academic and nonacademic programs evaluate reapplicants differently. METHODS: We sent an anonymous 19-question survey to 151 Accreditation Council for Graduate Medical Education (ACGME)-accredited orthopaedic surgery residency programs in five waves, 1 week apart (December 5, 2009-January 5, 2010). Investigators were blinded to the respondents' identities. RESULTS: Ninety-one of the 151 programs (60%) responded. Sixty-eight of the 91 programs (75%) stated they rarely accept unmatched applicants. Sixty-eight programs (75%) agreed an unmatched applicant should do a surgery internship for 1 year. Of the 36 programs that recommended a research year, 32 were academic programs. Academic programs were more likely than nonacademic programs to view as important new recommendations (85% versus 67%), minimum scores of 220 on Step I (67% versus 49%) and Step II (64% versus 36%), and AOA membership (85% versus 67%). CONCLUSIONS: By completing a surgical internship, unmatched students may increase their chances of matching. Students considering academic programs should ensure their academic record meets certain benchmarks and may consider a research year but risk limiting their acceptance to academic programs.

Marijuana Use is Not a Contraindication for Tranexamic Acid Utilization in Lumbar Spine Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to evaluate safety in lumbar spinal fusion with tranexamic acid (TXA) utilization in patients using marijuana. METHODS: This was a retrospective cohort study involving a single surgeon's cases of 1 to 4 level lumbar fusion procedures. Two hundred and ninety-four patients were followed for ninety days post-operatively. Consecutive patients were self-reported for daily marijuana use (n = 146) and compared to a similar cohort of patients who denied usage of marijuana (n = 146). Outcomes were collected, which included length of stay (LOS), estimated blood loss (EBL), post-operative myocardial infarction, seizures, deep venous thrombosis, pulmonary embolus, death, readmission, need for further surgery, infection, anaphylaxis, acute renal injury, and need for blood product transfusion. RESULTS: Patients in the marijuana usage cohort had similar age (58.9 years ±12.9 vs 58.7 years ±14.8, P = .903) and distribution of levels fused (P = .431) compared to the non-usage cohort. Thromboembolic events were rare in both groups (marijuana usage: 1 vs non-usage: 2). Compared to the non-usage cohort, the marijuana usage cohort had a similar average EBL (329.9 ± 298.5 mL vs 374.5 ± 363.8 mL; P = .254). Multivariate regression modeling demonstrated that neither EBL (OR 1.27, 95% CI 0.64-2.49) nor need for transfusion (OR 1.56, 95% CI 0.43-5.72) varied between cohorts. The non-usage cohort had twice the risk of prolonged LOS compared to the marijuana usage cohort (OR 2.05, 95% CI 1.15-3.63). CONCLUSION: Marijuana use should not be considered a contraindication for TXA utilization in lumbar spine surgery.

The Effects of Marijuana Use on Lumbar Spinal Fusion.

MINI: This study compared clinical and patient-reported outcomes following transforaminal lumbar interbody fusion between patients who use or do not use marijuana. We found that patients who use marijuana are younger, but do not demonstrate any differences in preoperative or postoperative Oswestry disability index scores or rates of fusion. STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The purpose of this study was to evaluate marijuana usage and its effect on outcomes following transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA: As marijuana becomes legalized throughout the United States, its medicinal and recreational usage is becoming more mainstream. Clinicians currently have little guidance regarding both short-term and long-term effects of marijuana usage on surgical interventions. While the rate of lumbar spinal fusion in the United States continues to grow, the effect of marijuana usage on fusion remains uncertain. METHODS: One hundred two patients who underwent TLIF performed by the same surgeon were followed for 12 months. Patients were self-reported for marijuana usage (n = 36). Patient reported outcome measures included preoperative Oswestry disability index (ODI), 6-month ODI, and 12-month ODI, as well as length of stay (LOS), complications, return to operating room (OR), revision surgery, and confirmed fusion. Continuous variables were compared using the independent two-sample t test or analysis of variance (ANOVA), whereas categorical variables were analyzed using the chi-square or Fischer exact tests. Adjusted analysis was performed using a multivariate logistic regression model. RESULTS: Marijuana usage was associated with a younger population (P < 0.001), but showed no difference regarding sex or body mass index compared with the non-usage group. There was no statistically significant difference in complications, return to OR, or revision surgery between groups. When controlling for factors such as age and preoperative ODI, multivariate analysis demonstrated that marijuana usage did not limit postoperative ODI reduction. The marijuana usage group demonstrated shorter LOS (2.42 vs. 3.00 d, P = 0.020). Fusion rates at 12 months were similar between groups (96% vs. 92.3%, P = 0.678). ODI was similar between groups at all time points. CONCLUSION: Perioperative outcomes were similar in patients who underwent TLIF regardless of marijuana usage. LEVEL OF EVIDENCE: 3.

A retrospective cohort study. The purpose of this study was to evaluate marijuana usage and its effect on outcomes following transforaminal lumbar interbody fusion (TLIF). As marijuana becomes legalized throughout the United States, its medicinal and recreational usage is becoming more mainstream. Clinicians currently have little guidance regarding both short-term and long-term effects of marijuana usage on surgical interventions. While the rate of lumbar spinal fusion in the United States continues to grow, the effect of marijuana usage on fusion remains uncertain. One hundred two patients who underwent TLIF performed by the same surgeon were followed for 12 months. Patients were self-reported for marijuana usage (n = 36). Patient reported outcome measures included preoperative Oswestry disability index (ODI), 6-month ODI, and 12-month ODI, as well as length of stay (LOS), complications, return to operating room (OR), revision surgery, and confirmed fusion. Continuous variables were compared using the independent two-sample t test or analysis of variance (ANOVA), whereas categorical variables were analyzed using the chi-square or Fischer exact tests. Adjusted analysis was performed using a multivariate logistic regression model. Marijuana usage was associated with a younger population (P < 0.001), but showed no difference regarding sex or body mass index compared with the non-usage group. There was no statistically significant difference in complications, return to OR, or revision surgery between groups. When controlling for factors such as age and preoperative ODI, multivariate analysis demonstrated that marijuana usage did not limit postoperative ODI reduction. The marijuana usage group demonstrated shorter LOS (2.42 vs. 3.00 d, P = 0.020). Fusion rates at 12 months were similar between groups (96% vs. 92.3%, P = 0.678). ODI was similar between groups at all time points. Perioperative outcomes were similar in patients who underwent TLIF regardless of marijuana usage. Level of Evidence: 3.

Trends in Spine Surgery Training During Neurological and Orthopaedic Surgery Residency: A 10-Year Analysis of ACGME Case Log Data.

BACKGROUND: Spine surgery training in the United States currently involves residency training in neurological or orthopaedic surgery. Because of different core residency surgical requirements, the volume of spine surgery procedures may vary between the 2 residencies. METHODS: We reviewed the Accreditation Council for Graduate Medical Education resident case logs for both orthopaedic surgery and neurological surgery for exposure to spine surgery procedures for the graduating years of 2009 to 2018. RESULTS: The average number of spine surgery procedures performed during that 10-year period was 433.8 for neurosurgery residents and 119.5 for orthopaedic surgery residents (p < 0.01). From 2009 to 2018, neurosurgery residents saw an increase of 26.5% in spine surgery procedures (from 389.6 to 492.9 procedures), whereas orthopaedic surgery residents saw a decrease of 41.3% (from 141.1 to 82.8 procedures). The 10-year average percentage of total spine procedures among all total surgical cases was 33.5% for neurosurgery residents compared with 6.2% for orthopaedic surgery residents (p < 0.01). This percentage decreased for both neurosurgery residents (35.8% in 2009 to 31.3% in 2018) and orthopaedic surgery residents (7.2% in 2009 to 4.9% in 2018). Neurosurgical residents performed 3.6 times more total spine procedures than orthopaedic surgery residents on average, a number that increased from 2.8-fold in 2009 to 6.0-fold in 2018. CONCLUSIONS: The case volume of spine surgery procedures varies greatly, with higher rates for neurological surgery and lower rates for orthopaedic surgery residencies, with an increasing discrepancy over time. Although case volume alone cannot solely determine quality of training, it is one measure to assess opportunities to develop optimal spine education around a certain accepted volume of surgical patient care. Not accounted for here are additional postgraduate spine cases performed by orthopaedic surgery residents who pursue spine fellowship training (an additional 300 to 500 cases). The results described herein may help to explore the various needs of and differences between residents seeking to pursue careers in spine as well as the role of spine surgery fellowships currently and in the future.

Does Knowledge of Implant Cost Affect Fixation Method Choice in the Management of Stable Intertrochanteric Hip Fractures?

We conducted a study to determine if knowledge of implant cost affects fixation method choice in the management of stable intertrochanteric hip fractures. We retrospectively reviewed the cases of 119 patients treated with a sliding hip screw (SHS; Versafix), a short Gamma nail (SGN), or a long Gamma nail (LGN). Of the 119 fractures, 71 were treated before implant costs were revealed, and 48 afterward. The 2 groups were similar in age, sex, fracture types, American Society of Anesthesiologists physical status classification, and preinjury ambulatory status. SHS was used in 38.0% of the before cases and 27.1% of the after cases, SGN in 29.6% of the before cases and 45.8% of the after cases, and LGN in 32.4% of the before cases and 27.1% of the after cases. Changes in implant use were not statistically significant. SHS was favored for 31-A1.1, 31-A1.2, and 31-A2.1 fractures in the before group but only for 31-A1.2 fractures in the after group. Gamma nails of both sizes were preferred in the after group for 31-A1.1, 31-A1.3, and 31-A2.1 fractures. At our institution, surgeon knowledge of implant cost did not affect fixation method choice in the management of stable intertrochanteric hip fractures.

Semitendinosus Graft for Interspinous Ligament Reinforcement in Adult Spinal Deformity.

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.].

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

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.

Reoperation Rates After 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 $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.

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

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.

Biomechanics of Degenerative Spinal Disorders.

The spine has several important functions including load transmission, permission of limited motion, and protection of the spinal cord. The vertebrae form functional spinal units, which represent the smallest segment that has characteristics of the entire spinal column. Discs and paired facet joints within each functional unit form a three-joint complex between which loads are transmitted. Surrounding the spinal motion segment are ligaments, composed of elastin and collagen, and joint capsules which restrict motion to within normal limits. Ligaments have variable strengths and act via different lever arm lengths to contribute to spinal stability. As a consequence of the longer moment arm from the spinous process to the instantaneous axis of rotation, inherently weaker ligaments (interspinous and supraspinous) are able to provide resistance to excessive flexion. Degenerative processes of the spine are a normal result of aging and occur on a spectrum. During the second decade of life, the intervertebral disc demonstrates histologic evidence of nucleus pulposus degradation caused by reduced end plate blood supply. As disc height decreases, the functional unit is capable of an increased range of axial rotation which subjects the posterior facet capsules to greater mechanical loads. A concurrent change in load transmission across the end plates and translation of the instantaneous axis of rotation further increase the degenerative processes at adjacent structures. The behavior of the functional unit is impacted by these processes and is reflected by changes in the stress-strain relationship. Back pain and other clinical symptoms may occur as a result of the biomechanical alterations of degeneration.

L5 pedicle subtraction osteotomy for high-grade isthmic spondylolisthesis.

To the authors' knowledge, this is the first article to present a pedicle subtraction osteotomy in the lumbar spine to correct and stabilize a high-grade isthmic spondylolisthesis, which poses many challenges with regard to treatment options and outcomes. The optimal surgical treatment for high-grade spondylolisthesis is controversial, but the goals of treatment are to stabilize the affected spinal levels and to decompress the neural elements. A pedicle subtraction osteotomy is a reconstructive procedure that addresses fixed sagittal imbalance by increasing lumbar lordosis through posterior spinal column shortening. The authors report a 46-year-old patient with chronic, progressively worsening back and leg radiculopathy accompanied by sagittal plane malalignment and for which a pedicle subtraction osteotomy was performed. The procedure yielded stabilization of the patient's lumbar spondylolisthesis and sagittal plane alignment was restoration. At 3 months postoperatively, the patient's pain had fully resolved and her motor and neurologic examination exhibited no deficits. At 24 months postoperatively, she was still symptom-free and ambulating without assistance. This report is the first documented successful pedicle subtraction osteotomy in the treatment of high-grade spondylolisthesis. This report indicates that certain patient populations may be amenable to pedicle subtraction osteotomy as a treatment option for pathology involving high-grade isthmic spondylolisthesis.

Percutaneous Sacroiliac Screw Fixation of the Posterior Pelvic Ring.

Percutaneous sacroiliac (SI) screw fixation is indicated for unstable posterior pelvic ring injuries, sacral fractures, and SI joint dislocations. This article provides a review of indications and contraindications, preoperative planning, imaging techniques and relevant anatomy, surgical technique, complications and their management, and outcomes after SI screw insertion.

Is formal decompression necessary for parameniscal cysts associated with meniscal tears?

BACKGROUND: Meniscal tears and associated parameniscal cysts have good outcomes after partial meniscectomy and cyst evacuation. Good outcomes have been noted after partial meniscectomy with recurrent cysts. This investigation asks if partial meniscectomy without meniscal cyst decompression is sufficient for positive patient outcome. METHODS: Sixteen patients treated between 2005 and 2010 for a meniscal cyst and concomitant meniscal tear. Inclusion criteria were meniscal tear and parameniscal cyst per MRI, no prior surgery on the affected knee, and Outerbridge classification of I/II. Two patients were excluded. Fourteen patients completed the study until final follow-up. Lysholm knee scores were documented at 6 months post-operatively and at final follow-up. Re-evaluation or second surgery of the treated knee was documented. RESULTS: Eight lateral cysts and six medial cysts were diagnosed. Eight cysts were associated with a horizontal cleavage tear, while six menisci had a complex tear with a horizontal cleavage component. The average cyst size was 1.3 cm (0.5 to 3.5) at the largest diameter. At 6 months, the average Lysholm knee score was 94.1. At mean 5 years, the average score was 89.1. Patients with medial cysts, cysts greater than 1.0 cm, horizontal cleavage tears, or without simultaneous chondroplasty scored higher in the short and medium-term than their respective counterparts. CONCLUSIONS: Excellent short and medium-term outcomes can be achieved following partial meniscectomy without cyst decompression for patients with meniscal cysts and associated meniscal tears. LEVEL OF EVIDENCE: Level IV.