Armen R. Deukmedjian

Analysis of lumbar plexopathies and nerve injury after lateral retroperitoneal transpsoas approach: diagnostic standardization

OBJECT The minimally invasive lateral transpsoas approach has become an increasingly popular means of fusion. The most frequent complication is related to lumbar plexus nerve injuries; these can be diagnosed based on distribution of neurological deficit following the motor and/or sensory nerve injury. However, the literature has failed to provide a clinically relevant description of these complications. With accurate clinical diagnosis, spine practitioners can provide more precise prognostic and management recommendations to include observation, nerve blocks, neurodestructive procedures, medications, or surgical repair strategies. The purpose of this study was to standardize the clinical findings of lumbar plexopathies and nerve injuries associated with minimally invasive lateral retroperitoneal transpsoas lumbar fusion. METHODS A thorough literature search of the MEDLINE database up to June 2012 was performed to identify studies that reported lumbar plexus and nerve injuries after the minimally invasive lateral retroperitoneal transpsoas approach. Included studies were assessed for described neurological deficits postoperatively. Studies that did attempt to describe nerve-related complications clinically were excluded. A clinically relevant assessment of lumbar plexus nerve injury was derived to standardize early diagnosis and outline prognostic implications. RESULTS A total of 18 studies were selected with a total of 2310 patients; 304 patients were reported to have possible plexus-related complications. The incidence of documented nerve and/or root injury and abdominal paresis ranged from 0% to 3.4% and 4.2%, respectively. Motor weakness ranged from 0.7% to 33.6%. Sensory complications ranged from 0% to 75%. A lack of consistency in the descriptions of the lumbar plexopathies and/or nerve injuries as well as a lack of diagnostic paradigms was noted across studies reviewed. Sensory dermal zones were established and a standardized approach was proposed. CONCLUSIONS There is underreporting of postoperative lumbar plexus nerve injury and a lack of standardization of clinical findings of neural complications related to the minimally invasive lateral retroperitoneal transpsoas approach. The authors provide a diagnostic paradigm that allows for an efficient and accurate classification of postoperative lumbar plexopathies and nerve injuries.

Complications in adult spinal deformity surgery: an analysis of minimally invasive, hybrid, and open surgical techniques.

OBJECT It is hypothesized that minimally invasive surgical techniques lead to fewer complications than open surgery for adult spinal deformity (ASD). The goal of this study was to analyze matched patient cohorts in an attempt to isolate the impact of approach on adverse events. METHODS Two multicenter databases queried for patients with ASD treated via surgery and at least 1 year of follow-up revealed 280 patients who had undergone minimally invasive surgery (MIS) or a hybrid procedure (HYB; n = 85) or open surgery (OPEN; n = 195). These patients were divided into 3 separate groups based on the approach performed and were propensity matched for age, preoperative sagittal vertebral axis (SVA), number of levels fused posteriorly, and lumbar coronal Cobb angle (CCA) in an attempt to neutralize these patient variables and to make conclusions based on approach only. Inclusion criteria for both databases were similar, and inclusion criteria specific to this study consisted of an age > 45 years, CCA > 20°, 3 or more levels of fusion, and minimum of 1 year of follow-up. Patients in the OPEN group with a thoracic CCA > 75° were excluded to further ensure a more homogeneous patient population. RESULTS In all, 60 matched patients were available for analysis (MIS = 20, HYB = 20, OPEN = 20). Blood loss was less in the MIS group than in the HYB and OPEN groups, but a significant difference was only found between the MIS and the OPEN group (669 vs 2322 ml, p = 0.001). The MIS and HYB groups had more fused interbody levels (4.5 and 4.1, respectively) than the OPEN group (1.6, p < 0.001). The OPEN group had less operative time than either the MIS or HYB group, but it was only statistically different from the HYB group (367 vs 665 minutes, p < 0.001). There was no significant difference in the duration of hospital stay among the groups. In patients with complete data, the overall complication rate was 45.5% (25 of 55). There was no significant difference in the total complication rate among the MIS, HYB, and OPEN groups (30%, 47%, and 63%, respectively; p = 0.147). No intraoperative complications were reported for the MIS group, 5.3% for the HYB group, and 25% for the OPEN group (p < 0.03). At least one postoperative complication occurred in 30%, 47%, and 50% (p = 0.40) of the MIS, HYB, and OPEN groups, respectively. One major complication occurred in 30%, 47%, and 63% (p = 0.147) of the MIS, HYB, and OPEN groups, respectively. All patients had significant improvement in both the Oswestry Disability Index (ODI) and visual analog scale scores after surgery (p < 0.001), although the MIS group did not have significant improvement in leg pain. The occurrence of complications had no impact on the ODI. CONCLUSIONS Results in this study suggest that the surgical approach may impact complications. The MIS group had significantly fewer intraoperative complications than did either the HYB or OPEN groups. If the goals of ASD surgery can be achieved, consideration should be given to less invasive techniques.

Management of sagittal balance in adult spinal deformity with minimally invasive anterolateral lumbar interbody fusion: a preliminary radiographic study

OBJECT Minimally invasive (MI) fusion and instrumentation techniques are playing a new role in the treatment of adult spinal deformity. The open pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) are proven segmental methods for improving regional lordosis and global sagittal parameters. Recently the MI anterior column release (ACR) was introduced as a segmental method for treating sagittal imbalance. There is a paucity of data in the literature evaluating the alternatives to PSO and SPO for sagittal balance correction. Thus, the authors conducted a preliminary retrospective radiographic review of prospectively collected data from 2009 to 2012 at a single institution. The objectives of this study were to: 1) investigate the radiographic effect of MI-ACR on spinopelvic parameters, 2) compare the radiographic effect of MI-ACR with PSO and SPO for treatment of adult spinal deformity, and 3) investigate the radiographic effect of percutaneous posterior spinal instrumentation on spinopelvic parameters when combined with MI transpsoas lateral interbody fusion (LIF) for adult spinal deformity. METHODS Patient demographics and radiographic data were collected for 36 patients (9 patients who underwent MI-ACR and 27 patients who did not undergo MI-ACR). Patients included in the study were those who had undergone at least a 2-level MI-LIF procedure; adequate preoperative and postoperative 36-inch radiographs of the scoliotic curvature; a separate second-stage procedure for the placement of posterior spinal instrumentation; and a diagnosis of degenerative scoliosis (coronal Cobb angle > 10° and/or sagittal vertebral axis > 5 cm). Statistical analysis was performed for normality and significance testing. RESULTS Percutaneous transpedicular spinal instrumentation did not significantly alter any of the spinopelvic parameters in either the ACR group or the non-ACR group. Lateral MI-LIF alone significantly improved coronal Cobb angle by 16°, and the fractional curve significantly improved in a subgroup treated with L5-S1 transforaminal lumbar interbody fusion. Fifteen ACRs were performed in 9 patients and resulted in significant coronal Cobb angle correction, lumbar lordosis correction of 16.5°, and sagittal vertebral axis correction of 4.8 cm per patient. Segmental analysis revealed a 12° gain in segmental lumbar lordosis and a 3.1-cm correction of the sagittal vertebral axis per ACR level treated. CONCLUSIONS The lateral MI-LIF with ACR has the ability to powerfully restore lumbar lordosis and correct sagittal imbalance. This segmental MI surgical technique boasts equivalence to SPO correction of these global radiographic parameters while simultaneously creating additional disc height and correcting coronal imbalance. Addition of posterior percutaneous instrumentation without in situ manipulation or overcorrection does not alter radiographic parameters when combined with the lateral MI-LIF.

Anterior longitudinal ligament release using the minimally invasive lateral retroperitoneal transpsoas approach: a cadaveric feasibility study and report of 4 clinical cases

OBJECT Traditional procedures for correction of sagittal imbalance via shortening of the posterior column include the Smith-Petersen osteotomy, pedicle subtraction osteotomy, and vertebral column resection. These procedures require wide exposure of the spinal column posteriorly, and may be associated with significant morbidity. Anterior longitudinal ligament (ALL) release using the minimally invasive lateral retroperitoneal approach with a resultant net lengthening of the anterior column has been performed as an alternative to increase lordosis. The objective of this study was to demonstrate the feasibility and early clinical experience of ALL release through a minimally invasive lateral retroperitoneal transpsoas approach, as well as to describe its surgical anatomy in the lumbar spine. METHODS Forty-eight lumbar levels were dissected in 12 fresh-frozen cadaveric specimens to study the anatomy of the ALL as well as its surrounding structures, and to determine the feasibility of the technique. The lumbar disc spaces and ALL were accessed via the lateral transpsoas approach and confirmed with fluoroscopy in each specimen. As an adjunct, 4 clinical cases of ALL release through the minimally invasive lateral retroperitoneal transpsoas approach were reviewed. Operative technique, results, complications, and early outcomes were assessed. RESULTS In the cadaveric study, sectioning of the ALL proved to be feasible from the minimally invasive lateral retroperitoneal transpsoas approach. The structures at most immediate risk during this procedure were the aorta, inferior vena cava, iliac vessels, and sympathetic plexus. The mean increase in segmental lumbar lordosis per level of ALL release was 10.2°, while global lumbar lordosis improved by 25°. Each level of ALL release took 56 minutes and produced 40 ml of blood loss on average. Visual analog scale and Oswestry Disability Index scores improved by 9 and 35 points, respectively. There were no cases of hardware failure, and as of yet no complications to report. CONCLUSIONS This initial experience suggests that ALL release through the minimally invasive lateral retroperitoneal transpsoas approach may be feasible, allows for improvement of lumbar lordosis without the need of an open laparotomy/thoracotomy, and minimizes the tissue disruption and morbidity associated with posterior osteotomies.

Postoperative lumbar plexus injury after lumbar retroperitoneal transpsoas minimally invasive lateral interbody fusion.

Study Design. Retrospective review. Objective. To evaluate the motor and sensory deficit rate after the lumbar retroperitoneal transpsoas minimally invasive lateral interbody fusion (MIS LIF) by reviewing a single surgeons experience. Summary of Background Data. The MIS LIF is an increasingly used alternative to traditional open anterior or posterior operations to treat a host of spinal disorders. It has many advantages, but the potential for immediate postoperative thigh numbness, pain, and potential motor weakness has been reported. Published rates range widely in part because previous studies have based patient outcomes on data from different surgeons using different techniques. Methods. An institutional review board-approved, retrospective review of a prospectively collected database was conducted. Seventy-one consecutive patients who underwent this procedure between L1 and L5 during a 3-year period met criteria and were included. Postoperative clinical examinations immediately after surgery and during routine follow-up intervals were examined. Results. There was a 19.1% (14/71) rate of immediate postoperative ipsilateral thigh numbness during the study period. The annual rates of numbness progressively decreased annually. There was a 26.1% (6/23), 25% (5/20), and 10.7% (3/28) rate for 2008, 2009, and 2010, respectively. All patients with numbness had a fusion construct that involved L4–L5. More than half the patients, 54.9% (39/71), had immediate postoperative ipsilateral iliopsoas or quadriceps weakness. Of these, the vast majority had resolution by 3 months (92.3%), and all had complete resolution by 2 years. Conclusion. The lumbar retroperitoneal transpsoas MIS LIF is a safe alternative to traditional open operations for many spinal conditions. As with most minimally invasive techniques, there is a learning curve to be overcome to minimize the risk of iatrogenic nerve injuries. Our refined technique of the MIS LIF during a 3-year period has led to a significant reduction of the incidence of postoperative numbness of nearly 60% (from 26.1%–10.7%).

Minimally invasive anterolateral corpectomy for spinal tumors.

Traditional open anterior and posterior approaches for the thoracic and thoracolumbar spine are associated with approach-related morbidity and limited surgical access to the level of abnormality. This article describes the minimally invasive anterolateral corpectomy for the treatment of spinal tumors, and reviews the current literature.

Percutaneous Minimally Invasive (MIS) Guide Wire-less Self-Tapping Pedicle Screw Placement in the Thoracic and Lumbar Spine: Safety and Initial Clinical Experience: Technical Note.

BACKGROUND: Multiple methods for minimally invasive (MIS) thoracic and lumbar pedicle screw placement exist. The guide wire is almost universally used for most insertion techniques; however, its use is not without complication and potentially prolongs surgical procedures. OBJECTIVE: To evaluate the safety of percutaneous MIS guide wire-less pedicle screw placement in the thoracic and lumbar spine at a single institution over a 3-year experience. METHODS: Forty-one patients who underwent posterior instrumentation with 110 transpedicular MIS thoracic and lumbar screws by a single surgeon from 2011 to 2014 were analyzed. The mean age was 63 years at the time of surgery. Etiological diagnoses were adult spinal deformity, trauma, spondylosis/spondylolisthesis, and other spinal diseases. Pedicle screws were inserted with the use of a guide wire-free technique in which anatomy-specific entry sites and fluoroscopic landmarks were used to guide the surgeon. A square, sharp-tipped pedicle screw was carefully advanced under biplanar fluoroscopic image (anteroposterior and lateral) down the pedicle into the body. No tapping or any type of electromonitoring was performed. An independent spine surgeon using medical records and thoracic/lumbar computed tomography taken during the postoperative period reviewed all patients. RESULTS: The number of the screws inserted at each level was as follows: total, 110; thoracic, 30; and lumbar, 80. All screws were evaluated by computed tomography to assess screw position. Seven screws (6.3%) were inserted with moderate cortical perforation, including 3 screws (2.7%) that violated the medial wall. There were no neurological, vascular, or visceral complications with up to 3 years of follow-up. CONCLUSION: The percutaneous MIS guide wire-less technique of lumbar and thoracic pedicle screw placement performed using a biplanar fluoroscopic guidance in a stepwise, consistent manner is an accurate, safe, and reproducible method of insertion to treat a variety of spinal disorders. ABBREVIATIONS: MIS, minimally invasive spine TP, transverse process

Chance fractures in the pediatric population

OBJECT The pediatric Chance fracture (PCF) is an uncommon injury, but it has been increasingly reported. Knowledge is limited to few case reports and short series. To understand the various aspects of this injury, the authors reviewed the current literature. METHODS A literature search was conducted using the PubMed and Ovid online databases and relevant key words. All articles that were in English and provided information regarding PCF as a sole or part of the objective were retrieved. RESULTS Seventy-three articles were found to fulfill the inclusion criteria. Relevant information about PCF collected from these articles included: 1) mode of trauma, 2) associated injuries, 3) radiological classification, and 4) treatment. CONCLUSIONS Chance fractures in children are potentially devastating injuries largely caused by motor vehicle collisions, and these fractures may be more common than previously thought. Concomitant intraabdominal injuries are common and should be suspected, particularly when a seat belt sign is observed. Blunt abdominal aortic injuries are rarely associated, but should be evaluated for and treated appropriately. Magnetic resonance imaging is best for defining ligamentous injury, which aids in defining the pattern of injury, facilitating appropriate treatment regimens.

Minimally Invasive Anterior Column Reconstruction for Sagittal Plane Deformities

Many factors are involved in the surgical management of adult spinal deformity, including maintenance of coronal and sagittal balance as well as spinopelvic harmony [1–5]. Adult spinal deformity (ASD) is believed to develop because of asymmetrical degeneration of discs, osteoporosis, and vertebral body compression fractures [6]. Presenting symptoms of this condition primarily include radiculopathy, chronic low back pain, and neurogenic claudication caused by concurrent spinal stenosis [7, 8].

Medically treated prolactin-secreting pituitary adenomas: when should we operate?

Abstract Background. The incidence of medical failure for prolactin (PRL)-secreting pituitary tumours is not well known. Object. The purpose of this study is to report clinical, radiographic and laboratory findings of PRL-secreting tumours that predict failed medical management. Methods. An analysis of 92 consecutive patients was performed that met the inclusion criteria. Decision for surgery was made based on failure of dopamine agonists to either control clinical symptoms and normalise hormonal level or diminish mass effect on follow-up evaluation. Results. Of the 92 patients treated, 14 patients (15%) required trans-nasal, trans-sphenoidal pituitary surgery (TSS). One patient underwent surgery for repair of a skull defect and 13 patients (14%) required surgery after failed medical management. Higher initial PRL was statistically significant regarding the need for surgical intervention, but a persistently abnormal level after initiation of treatment was a more significant predictor (Fisher exact test, p = 0.005 vs. p < 0.001). Size was also a statistically significant factor (p = 0.014); macroadenomas had a relative risk of 9.27 (95% CI: 1.15–74.86) for needing surgery compared to microadenomas. In addition, macroadenomas with cavernous sinus (CS) extension and pre-operative visual field deficit demonstrated a strong tendency for surgical intervention. Conclusion. Medical management remains the most effective treatment option for prolactinomas. A partial hormonal response to medical management seems to be the most significant predictive factor but adenomas > 20 mm, visual field deficit and invasion of the CS may help predict the need for surgery. We suggest a minimum trial period (at least 8 weeks) of medical treatment prior to the consideration of surgery.