Transabdominal motor evoked potential neuromonitoring of lumbosacral spine surgery

BACKGROUND CONTEXT

Transcranial Motor Evoked Potentials (TcMEPs) can improve intraoperative detection of femoral plexus and nerve root injury during lumbosacral spine surgery. However, even under ideal conditions, TcMEPs are not completely free of false-positive alerts due to the immobilizing effect of general anesthetics, especially in the proximal musculature. The application of transcutaneous stimulation to activate ventral nerve roots directly at the level of the conus medularis (bypassing the brain and spinal cord) has emerged as a method to potentially monitor the motor component of the femoral plexus and lumbosacral nerves free from the blunting effects of general anesthesia.

PURPOSE

To evaluate the reliability and efficacy of transabdominal motor evoked potentials (TaMEPs) compared to TcMEPs during lumbosacral spine procedures.

DESIGN

We present the findings of a single-center 12-month retrospective experience of all lumbosacral spine surgeries utilizing multimodality intraoperative neuromonitoring (IONM) consisting of TcMEPs, TaMEPs, somatosensory evoked potentials (SSEPs), electromyography (EMG), and electroencephalography.

PATIENT SAMPLE

Two hundred and twenty patients having one, or a combination of lumbosacral spine procedures, including anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), posterior spinal fusion (PSF), and/or transforaminal lumbar interbody fusion (TLIF).

OUTCOME MEASURES

Intraoperative neuromonitoring data was correlated to immediate post-operative neurologic examinations and chart review.

METHODS

Baseline reliability, false positive rate, true positive rate, false negative rate, area under the curve at baseline and at alerts, and detection of pre-operative deficits of TcMEPs and TaMEPs were compared and analyzed for statistical significance. The relationship between transcutaneous stimulation voltage level and patient BMI was also examined.

RESULTS

TaMEPs were significantly more reliable than TcMEPs in all muscles except abductor hallucis. Of the 27 false positive alerts, 24 were TcMEPs alone, and 3 were TaMEPs alone. Of the 19 true positives, none were detected by TcMEPs alone, 3 were detected by TaMEPs alone (TcMEPs were not present), and the remaining 16 true positives involved TaMEPs and TcMEPs. TaMEPs had a significantly larger area under the curve (AUC) at baseline than TcMEPs in all muscles except abductor hallucis. The percent decrease in TcMEP and TaMEP AUC during LLIF alerts was not significantly different. Both TcMEPs and TaMEPs reflected three pre-existing motor deficits. Patient BMI and TaMEP stimulation intensity were found to be moderately positively correlated.

CONCLUSIONS

These findings demonstrate the high reliability and predictability of TaMEPs and the potential added value when TaMEPs are incorporated into multimodality IONM during lumbosacral spine surgery.

The utility of intraoperative neuromonitoring on simple posterior lumbar fusions-analysis of the National Inpatient Sample

BACKGROUND

Several studies have demonstrated the utility of intraoperative neuromonitoring (IOM) including somatosensory evoked potentials (SSEPs), motor-evoked potentials (MEPs), and electromyography (EMG), in decreasing the risk of neurologic injury in spinal deformity procedures. However, there is limited evidence supporting the routine use of IOM in elective posterolateral lumbar fusion (PLF).

METHODS

The National Inpatient Sample (NIS) was analyzed for the years 2012-2015 to identify patients undergoing elective PLF with (n=22,404) or without (n=111,168) IOM use. Statistical analyses were conducted to assess the impact of IOM on length of stay, total charges, and development of neurologic complications. These analyses controlled for age, gender, race, income percentile, primary expected payer, number of reported comorbidities, hospital teaching status, and hospital size.

RESULTS

The overall use of IOM in elective PLFs was found to have increased from 14.6% in the year 2012 to 19.3% in 2015. The total charge in hospitalization cost for all patients who received IOM increased from $129,384.72 in 2012 to $146,427.79 in 2015. Overall, the total charge of hospitalization was 11% greater in the IOM group when compared to those patients that did not have IOM (P<0.001). IOM did not have a statistically significant impact on the likelihood of developing a neurological complication.

CONCLUSIONS

While there may conceivably be benefits to the use of this technology in complex revision fusions or pathologies, we found no meaningful benefit of its application to single-level index PLF for degenerative spine disease.

Hybrid Anterior Column Realignment-Pedicle Subtraction Osteotomy for Severe Rigid Sagittal Deformity

OBJECTIVE

Recently, a hybrid anterior column realignment-pedicle subtraction osteotomy (ACR-PSO) approach has been conceived for patients with severe rigid sagittal deformity, the clinical and radiographic outcomes of which require further investigation compared with ACR only.

METHODS

A single-center, retrospective chart review identified patients undergoing a combination of hyperlordotic lateral lumbar interbody grafting (ACR) and concurrent Schwab grade 3 three-column osteotomy and propensity-matched patients undergoing ACR only in the same time frame. Anterior longitudinal ligament was directly released or partially sectioned in all patients. Chart data included demographics, Oswestry Disability Index scores, ACR and osteotomy locations, cage dimensions, fusion length, and complications. Radiographic measurements included lumbar lordosis, sagittal vertical axis, pelvic tilt (PT), and proximal junctional kyphosis.

RESULTS

Fourteen patients were enrolled in the ACR + PSO group and 36 in the ACR-only group. Mean ages were 68.5 and 63.9 years, 64% and 67% were female, average body mass index was 27.9 and 29.2, and cardiopulmonary comorbidities were 21% and 17%, respectively. There was no difference in complications (P = 0.347). The average follow-up for the ACR + PSO and ACR-only groups were 22 and 18 months, respectively. Excluding 2 mortalities, fusion occurred in all patients. Average change in lumbar lordosis measured -40.8 ± 9.2 degrees and -19.1 ± 15.7 degrees (P = 0.0006), and PT correction measured 10.5 ± 3.4 degrees and 27.3 ± 1.6 degrees (P < 0.0001), respectively.

CONCLUSIONS

For patients with severe rigid sagittal deformity, the hybrid ACR-PSO approach offers significant restoration of lumbar lordosis compared with ACR only, with similar complications but reduced PT correction.

Resection of Spinal Meningioma Using Ultrasonic BoneScalpel Microshaver: Cases, Technique, and Review of the Literature

BACKGROUND

Meningiomas of the spinal canal comprise up to 40% of all spinal tumors. The standard management of these tumors is gross total resection. The outcome and extent of resection depends on location, size, patient's neurologic status, and experience of the surgeon. Heavily calcified spinal meningiomas often pose a challenge for achieving gross total resection without cord injury.

OBJECTIVE

To report our experience with the BoneScalpel Micro-shaver to resect heavily calcified areas of spinal meningiomas adherent to the spinal cord without significant cord manipulation, achieving gross total resection and outstanding clinical results.

METHODS

Seventy-nine and 82-yr-old females presented with progressive leg weakness, paresthesias, and gait instability. Magnetic resonance imaging of the thoracic spine showed a homogenous enhancing intradural extramedullary mass with mass effect on the spinal cord. Midline bilateral laminectomy was performed, and the dura was open in midline. The lateral portion of the tumor away from the spinal cord was resected with Cavitron Ultrasonic Surgical Aspirator while the BoneScalpel Micro-shaver (power level 5 and 30% irrigation) was brought into the field for the calcified portion of the tumor adherent to the spinal cord.

RESULTS

Gross total resection was achieved for both cases. At the 2-wk postoperative visit, both patients reported complete recovery of their leg weakness with significant improvement in paresthesias and ataxia.

CONCLUSION

The ultrasonic osteotome equipped with a microhook tip appears to be a safe surgical instrument allowing for effective resection of spinal meningiomas or other heavily calcified spinal masses not easily removed by usual surgical instrumentation.

Complications associated with L4-5 anterior retroperitoneal trans-psoas interbody fusion: a single institution series

Background

Lateral lumbar interbody fusion (LLIF), first described in the literature in 2006 by Ozgur et al., involves direct access to the lateral disc space via a retroperitoneal trans-psoas tubular approach. Neuromonitoring is vital during this approach since the surgical corridor traverses the psoas muscle where the lumbar plexus lies, risking injury to the lumbosacral plexus that could result in sensory or motor deficits. The risk of neurologic injury is especially higher at L4-5 due to the anatomy of the plexus at this level. Here we report our single-center clinical experience with L4-5 LLIF.

Methods

A retrospective chart review of all patients who underwent an L4-5 LLIF between May 2016 and March 2019 was performed. Baseline demographics and clinical characteristics, such as body mass index (BMI), medical comorbidities, surgical history, tobacco status, operative time and blood loss, length of stay (LOS), and post-op complications were recorded.

Results

A total of 220 (58% female and 42% male) cases were reviewed. The most common presenting pathology was spondylolisthesis. The average age, BMI, operative time, blood loss, and LOS were 64.6 years, 29 kg/m², 214 min, 75 cc, and 2.5 days respectively. A review of post-operative neurologic deficits revealed 31.4% transient hip flexor weakness and 4.5% quadricep weakness on the approach side. At 3-week follow-up, 9.1% of patients experienced mild hip flexor weakness (4 or 4+/5), 0.9% reported mild quadricep weakness, and 9.5% reported anterior thigh dysesthesias; 93.2% of patients were discharged home and 2.3% were readmitted within the first 30 days post discharge. Female sex, higher BMI and longer operative time were associated with hip flexor weakness.

Conclusions

LLIF at L4-5 is a safe, feasible, and versatile approach to the lumbar spine with an acceptable approach-related sensory and motor neurologic complication rates.

Utility of Patient-Specific Rod Instrumentation in Deformity Correction: Single Institution Experience

Introduction

Patient-specific instrumentation is an emerging technology with the promise of a better fit to patient anatomy. With the advent of deformity correction planning software, prefabricated rods can mitigate the need to bend rods in the operating room. Prefabricated rods allow the surgeon to provide a deformity correction closely in line with the surgical plan.

Methods

A retrospective chart review was completed, and all patients with Medicrea UNiD rod were included. A minimum of 3 week follow up upright 36-inch lateral radiograph was necessary for analysis. Overall 21 patients had Medicrea UNiD rods placed; four were excluded (one for cervicothoracic fusion, three for incomplete follow up). Pelvic parameters were documented from the preoperative, surgical plan, and postoperative radiographs using Surgimap (Nemaris Inc, NY). The parameters for the rods were based on the surgical plan. Paired t-tests were used to compare the preoperative, surgical plan, and postoperative pelvic parameters.

Results

Average lumbar lordosis, pelvic tilt, sacral slope, and sagittal vertical axis in preoperative radiographs were 35.12°, 24.82°, 28.65°, and 65.65 mm, respectively. In postoperative imaging, lumbar lordosis, pelvic tilt, sacral slope, and sagittal vertical axis were 57.00°, 18.00°, 35.71°, and 21.59 mm, respectively. There was a statistically significant difference in pelvic tilt, sacral slope, lumbar lordosis, and sagittal vertical axis between the preoperative film and surgical plan (p < 0.001), whereas no statistically significant difference was found between the surgical plan and postoperative pelvic parameters (p > 0.05).

Conclusions

Cases in which prefabricated rods were utilized demonstrated improved spinopelvic alignment. Additionally, there was no statistical difference between the surgical plan and postoperative imaging in terms of pelvic parameters. Future studies are needed to investigate the possible benefits of prefabricated rods.

Minimally Invasive, Stereotactic, Wireless, Percutaneous Pedicle Screw Placement in the Lumbar Spine: Accuracy Rates With 182 Consecutive Screws

BACKGROUND

Standard fluoroscopic navigation and stereotactic computed tomography-guided lumbar pedicle screw instrumentation traditionally relied on the placement of Kirshner wires (K-wires) to ensure accurate screw placement. The use of K-wires, however, is associated with a risk of morbidity due to potential ventral displacement into the retroperitoneum. We report our experience using a computer image-guided, wireless method for pedicle screw placement. We hypothesize that minimally invasive, wireless pedicle screw placement is as accurate and safe as the traditional technique using K-wires while decreasing operative time and avoiding potential complications associated with K-wires.

METHODS

We conducted a retrospective review of 42 consecutive patients who underwent a stereotactic-guided, wireless lumbar pedicle screw placement. All screws were placed to provide fixation to a variety of interbody fusion constructs including anterior lumbar interbody fusion, lateral interbody fusion, and transforaminal lumbar interbody fusion. The procedures were performed using the O-arm intraoperative imaging system with StealthStation navigation (Medtronic, Memphis, TN) and Medtronic navigated instrumentation. After placing a percutaneous navigation frame into the posterior superior iliac spine or onto an adjacent spinous process, an intraoperative O-arm image was obtained to allow subsequent StealthStation navigation. Para-median incisions were selected to allow precise percutaneous access to the target pedicles. The pedicles were cannulated using either a stereotactic drill or a novel awl-tipped tap along with a low-speed/high-torque power driver. The initial trajectory into the pedicle was recorded on the Medtronic StealthStation prior to removal of the drill or awl-tap, creating a "virtual" K-wire rather than inserting an actual K-wire to allow subsequent tapping and screw insertion. Accurate screw placement is achieved by following the virtual path as an exact computer-aided design model of the screw traversing the pedicle is projected onto the display and by using audible and tactile feedback. A second O-arm scan was obtained to confirm accuracy of screw placement.

RESULTS

A total of 20 women and 22 men (average age = 56 years) underwent a total of 182 pedicle screw placements using the stereotactic, wireless technique. The total breach rate was 9.9%, with a clinically significant breach rate of 0% (defined as >2 mm medial breach or >4 mm lateral breach) and a clinical complication rate of 0%.

CONCLUSIONS

Wireless, percutaneous placement of lumbar pedicle screws using computed tomography-guided stereotactic navigation is a safe, reproducible technique with very high accuracy rates.

Sagittal plane lumbar intervertebral motion during seated flexion-extension radiographs of 658 asymptomatic nondegenerated levels

OBJECT

Evaluation of lumbar stability is fundamentally dependent on a clear understanding of normal lumbar motion. There are inconsistencies in reported lumbar motion across previously published studies, and it is unclear which provide the most reliable reference data. New technology now allows valid and reliable determination of normal lumbar intervertebral motion (IVM). The object of this study was to provide normative reference data for lumbar IVM and center of rotation (COR) using validated computer-assisted measurement tools.

METHODS

Sitting flexion-extension radiographs were obtained in 162 asymptomatic volunteers and then analyzed using a previously validated and widely used computerized image analysis method. Each lumbar level was subsequently classified as “degenerated” or “nondegenerated” using the Kellgren-Lawrence classification. Of the 803 levels analyzed, 658 were nondegenerated (Kellgren-Lawrence grade < 2). At each level of the lumbar spine, the magnitude of intervertebral rotation and translation, the ratio of translation per degree of rotation (TPDR), and the position of the COR were calculated in the nondegenerative cohort. Translations were calculated in millimeters and percentage endplate width.

RESULTS

All parameters were significantly dependent on the intervertebral level. The upper limit of the 95% CIs for anteroposterior intervertebral translation in this asymptomatic cohort ranged from 2.1 mm (6.2% endplate width) to 4.6 mm (13.3% endplate width). Intervertebral rotation upper limits ranged from 16.3° to 23.5°. The upper limits for TPDR ranged from 0.49% to 0.82% endplate width/degree. The COR coordinates were clustered in level-dependent patterns.

CONCLUSIONS

New normal values for IVM, COR, and the ratio of TPDR in asymptomatic nondegenerative lumbar levels are proposed, providing a reference for future interpretation of sagittal plane motion in the lumbar spine.

Acute Onset of Guillain-Barré Syndrome After Elective Spinal Surgery

BACKGROUND

Guillain-Barré syndrome (GBS) is an acute peripheral neuropathy caused by an autoimmune response against myelin of peripheral nerves. GBS has been reported after surgery, in general, and after spinal surgery, in particular. In most cases, GBS developed 1-3 weeks after surgery.

METHODS

Report of 2 cases of GBS after elective spine surgery that developed in the immediate postoperative period.

RESULTS

Within 1 and 3 hours after surgery, respectively, both patients developed ascending loss of motor and sensory function. They were taken back urgently to the operating room for wound exploration to ensure that an epidural hematoma had not developed. Cerebrospinal fluid studies and electromyography/nerve conduction velocity were then rapidly obtained and were compatible with acute inflammatory demyelinating polyradiculoneuropathy. Therapy was initiated with administration of intravenous immunoglobulin and plasmapheresis. Both patients made substantial motor recovery during the course of 1-2 years but have residual sensory abnormalities.

CONCLUSIONS

GBS developing acutely after spinal surgery is a rare occurrence but should be considered in the differential diagnosis of neurological deterioration after surgery. Rapid diagnosis and treatment are essential for recovery of neurological function.

Lateral retroperitoneal transpsoas interbody fusion in a patient with achondroplastic dwarfism

The authors present the first reported use of the lateral retroperitoneal transpsoas approach for interbody arthrodesis in a patient with achondroplastic dwarfism. The inherent anatomical abnormalities of the spine present in achondroplastic dwarfism predispose these patients to an increased incidence of spinal deformity as well as neurogenic claudication and potential radicular symptoms. The risks associated with prolonged general anesthesia and intolerance of significant blood loss in these patients makes them ideal candidates for minimally invasive spinal surgery. The patient in this case was a 51-year-old man with achondroplastic dwarfism who had a history of progressive claudication and radicular pain despite previous extensive lumbar laminectomies. The lateral retroperitoneal transpsoas approach was used for placement of interbody cages at L1/2, L2/3, L3/4, and L4/5, followed by posterior decompression and pedicle screw instrumentation. The patient tolerated the procedure well with no complications. Postoperatively his claudicatory and radicular symptoms resolved and a CT scan revealed solid arthrodesis with no periimplant lucencies.

Spinal extradural arteriovenous fistulas: a clinical and radiological description of different types and their novel treatment with Onyx

Object

Spinal extradural (epidural) arteriovenous fistulas (AVFs) are uncommon vascular lesions of the spine with arteriovenous shunting located primarily in the epidural venous plexus. Understanding the complex anatomical variations of these uncommon lesions is important for management. The authors describe the different types of spinal extradural AVFs and their endovascular management using Onyx.

Methods

Eight spinal extradural AVFs in 7 patients were studied using MR imaging, spinal angiography, and dynamic CT (DynaCT) between 2005 and 2009. Special consideration was given to the anatomy, pattern of venous drainage, and mass effect upon the nerve roots, spinal cord, and vertebrae.

Results

The neuroaxial location of the 8 spinal extradural AVFs was lumbosacral in 1 patient, lumbar in 4 patients, thoracic in 2 patients, and cervical in 1 patient. Spinal extradural AVFs were divided into 3 types. In Type A spinal extradural AVFs, arteriovenous shunting occurs in the epidural space and these types have an intradural draining vein causing venous hypertension and spinal cord edema with associated myelopathy or cauda equina syndrome. Type B1 malformations are confined to the epidural space with no intradural draining vein, causing compression of the spinal cord and/or nerve roots with myelopathy and/or radiculopathy. Type B2 malformations are also confined to the epidural space with no intradural draining vein and no mass effect, and are asymptomatic. There were 4 Type A spinal extradural AVFs, 3 Type B1s, and 1 Type B2. Onyx was used in all cases for embolization. Follow-up at 6–24 months showed that 4 patients experienced excellent recovery. Three patients with Type A spinal extradural AVFs attained good motor recovery but experienced persistent bladder and/or bowel problems.

Conclusions

The current description of the different types of spinal extradural AVFs can help in understanding their pathophysiology and guide management. DynaCT was found to be useful in understanding the complex anatomy of these lesions. Endovascular treatment with Onyx is a good alternative for spinal extradural AVF management.

Iatrogenic pyogenic osteomyelitis of C-1 and C-2 treated with transoral decompression and delayed posterior occipitocervical arthrodesis. Case report

The authors describe a case of osteomyelitis of the craniocervical junction caused by iatrogenic infection of the spine during corticosteroid injection therapy. This 58-year-old diabetic man presented with acute exacerbation of neck pain that had began 4 months prior to admission. He did not experience the associated fever, chills, or sweats, but he did notice transient weakness in the right upper extremity. A computed tomography (CT) scan of the cervical spine demonstrated a destructive process involving the odontoid and the left occipitocervical and atlantoaxial joints that was not present on a CT obtained 2 months earlier, just before trigger-point and left-sided C1-2 facet joint corticosteroid injections. A diagnosis of staphylococcal osteomyelitis was made, and initial treatment with external immobilization and appropriate antibiotic therapy failed to control radiographically demonstrated and clinical progression. The patient was successfully treated using staged anterior decompression and posterior instrumented fusion with prolonged antibiotic therapy. To the authors' knowledge this case is the first reported instance of iatrogenic pyogenic osteomyelitis of the craniocervical junction successfully treated with anterior decompression and delayed posterior arthrodesis.

Surgical management of metastatic disease of the lumbar spine: experience with 139 patients

Object. The surgical treatment of metastatic spinal tumors is an essential component of the comprehensive care of cancer patients. In most large series investigators have focused on the treatment of thoracic lesions because 70% of cases involve this region. The lumbar spine is less frequently involved (20% cases), and it is unclear whether its unique anatomical and biomechanical features affect surgery-related outcomes. The authors present a retrospective study of a large series of patients with lumbar metastatic lesions, assessing neurological and pain outcomes, complications, and survival.

Methods. The authors retrospectively reviewed data obtained in 139 patients who underwent 166 surgical procedures for lumbar metastatic disease between August 1994 and April 2001. The impact of operative approach on outcomes was also analyzed.

Among the wide variety of metastatic lesions, pain was the most common presenting symptom (96%), including local pain, radicular pain, and axial pain due to instability. Patients underwent anterior, posterior, and combined approaches depending on the anatomical distribution of disease. One month after surgery, complete or partial improvement in pain was demonstrated in 94% of the cases. The median survival duration for the entire population was 14.8 months.

Conclusions. The surgical treatment of metastatic lesions in the lumbar spine improved neurological and ambulatory function, significantly reducing axial spinal pain; results were comparable with those for other spinal regions. Analysis of results obtained in the present study suggests that outcomes are similar when the operative approach mirrors the anatomical distribution of disease. When lumbar vertebrectomy is necessary, however, anterior approaches minimize blood loss and wound-related complications.

Naturally acquired babesiosis in a reindeer (Rangifer tarandus tarandus) herd in Great Britain

A provisional diagnosis of babesiosis was made in a reindeer herd in Scotland when seven animals died during 1997 and 1998. Additional clinical cases occurred, but the animals recovered after treatment. Thirty-one reindeer from the herd were tested for the prevalence of exposure to Babesia by the indirect fluorescent antibody test using a bovine isolate of Babesia divergens that had been passaged through gerbils. Infection rates were determined by Giemsa-stained blood smears. In addition, molecular identification of the infecting Babesiasp. was undertaken using SSU rRNA gene sequence analysis. It is likely that the organism causing babesiosis in this reindeer herd is B. divergens.

Genotypically unique Babesia spp. isolated from reindeer (Rangifer tarandus tarandus) in the United States

Two morphologically dissimilar Babesia spp. were cultured from reindeer (Rangifer tarandus tarandus) in Placer County, Calif. The smaller isolate, designated RD61, was morphologically similar to Babesia odocoilei. Serum from RD61-infected reindeer reacted equally strongly to B. odocoilei and RD61 parasites in the indirect fluorescent antibody (IFA) test. Small subunit ribosomal RNA (SSU rRNA) gene-sequence analysis showed 99.0% identity to that of B. odocoilei. The larger piroplasm, designated RD63, resembled larger babesia organisms, such as Babesia caballi and Babesia bigemina. Serum from RD63-infected reindeer also reacted with both B. odocoilei and RD61 parasites in the indirect fluorescent antibody test. The SSU rRNA gene showed 94.2% identity to that of B. bigemina. Further studies are needed to determine whether these parasites are the same as the Babesia spp. previously documented in Siberian reindeer.

Antigenic, phenotypic and molecular characterization confirms Babesia odocoilei isolated from three cervids

Babesia isolates from an elk (Cervus elaphus canadensis) and a caribou (Rangifer tarandus caribou) with fatal infections were compared to Babesia odocoilei (Engeling isolate) from white-tailed deer (Odocoileus virginianus) by experimental infection, serologic, and small subunit ribosomal RNA (SSU rRNA) gene sequence analysis studies. Both the indirect fluorescent antibody test and immunoprecipitation assays demonstrated antigenic variation among the isolates. Experimental infection studies showed no clinical differences among the isolates. Nucleotide sequence analysis showed that the elk and caribou Babesia sp. isolates possessed SSU rRNA genes with identical sequences to that of B. odocoilei. A phylogenetic tree constructed from SSU rRNA gene sequences shows that B. odocoilei is most closely related to Babesia divergens, both of which branch together in the true babesia clade.

A common high molecular weight antigen of Babesia bovis isolates from Mexico

Cattle from an area of Mexico endemic with Babesia bovis infections have a dominant antibody response to a 152kDa antigen of the Tamaulipas strain of B. bovis. A mAb termed PB/5, showing a specific reactivity to this 152kDa antigen in Western blots, was identified. The mAb which reacted with the blunt end of B. bovis in an indirect fluorescent antibody test also reacted to a 152kDa antigen in two other isolates (Nuevo Leon and Yucatan), and a 175kDa antigen in the Huasteca B. bovis isolate from Mexico. Polyclonal monospecific sera from a calf inoculated with mAb-affinity purified 152kDa antigen (Tamaulipas strain) identified B. bovis by the indirect fluorescent antibody test and two antigens of B. bovis (65kDa and 152kDa) in Western blot. Since the epitope reacting to the mAb PB/5 is conserved, this antigen provides a basis for developing a diagnostic test or an immunogen.

A study of the systematics of Theileria spp. based upon small-subunit ribosomal RNA gene sequences

The systematics of benign and moderately pathogenic Theileria isolates from cattle and deer originating from different geographic regions was undertaken by small-subunit ribosomal RNA (SSU rRNA) gene nucleotide-sequence analysis. A maximum-likelihood phylogenetic tree constructed from these sequences resulted in two major divisions, each with a common ancestor. One major division branches into four relatively divergent groups, including (1) bovine Theileria sp. Type D (USA and Korea), (2) T. mutans Intona and Theileria sp. MSD (Africa), (3) T. cervi (USA), and (4) well-characterized pathogenic Theileria spp. (Africa). The other major division branches into two groups: (1) T. buffeli Warwick and T. buffeli Marula and (2) a second branch of closely related isolates with SSU rRNA gene Types B, B1, C, E, and H. Putative geographically associated diversity was noted only in the Korean bovine Theileria spp. with SSU rRNA gene types C and H and in African T. mutans Intona and Theileria sp. MSD. The current results show that the United States bovine Theileria isolates are not T. mutans because they have T. buffeli Marula (Type A) and/or Type D (species undesignated) SSU rRNA gene sequences. The taxonomic separation of T. buffeli Warwick from African T. mutans is confirmed in this study.

Theileria sp. Infections associated with bovine fatalities in the United States confirmed by small-subunit rRNA gene analyses of blood and tick samples

Theileria sp.-specific small subunit (SSU) rRNA gene amplification confirmed the presence of the organism in cattle and in Amblyomma americanum and Dermacentor variabilis ticks collected from a cattle herd in Missouri. Blood from the index animal had type A and type D Theileria SSU rRNA genes. The type D gene was also found in blood from two cohort cattle and tick tissues. The type A SSU rRNA gene was previously reported from bovine Theileria isolates from Texas and North Carolina; the type D gene was reported from a Texas cow with theileriosis.

Two Theileria cervi SSU RRNA gene sequence types found in isolates from white-tailed deer and elk in North America

Two Theileria cervi SSU rRNA gene sequence Types, F and G, from white-tailed deer (Odocoileus virginianus) and elk (Cervus elaphus canadensis) isolates in North America were confirmed. Previously, nucleotide sequencing through a single variable (V4) region showed the presence of SSU rRNA gene Types F and G in T. cervi isolates from white-tailed deer and an elk. In this study, both sequence types were found in four T. cervi isolates (two from deer and two from elk). Microheterogeneity only appeared in the Type G gene, resulting in Subtypes G1, G2 and G3. Subtype G1 was found in two elk and one white-tailed deer T. cervi isolate; Subtypes G2 and G3 were found in a white-tailed deer T. cervi isolate. The Type F SSU rRNA genes were identical in nucleotide sequence in both elk and white-tailed deer T. cervi isolates. The high degree of conservation in the Type F variable regions may be exploited to design specific oligonucleotide primers for parasite detection by the polymerase chain reaction in cervine or tick hosts.

Babesia equi field isolates cultured from horse blood using a microcentrifuge method

Babesia equi, a causative agent of equine piroplasmosis, was isolated from horses in the Chaco Province of Argentina, a known piroplasmosis endemic region. Fifteen B. equi field isolates were acquired by culture from 23 actively working horses from 2 ranches. The horses appeared healthy with no clinical signs or histories indicative of equine piroplasmosis. All 23 horses had B. equi-specific antibody activity by the indirect fluorescent antibody test and 18 were also complement fixation test positive for B. equi. Equine erythrocytes were prepared for parasite culture using a microcentrifuge tube method. This method greatly reduces the time involved in cell handling and parasite exposure to ambient conditions. By this method, B. equi cultures can be initiated from very small quantities of blood.

Identical small subunit ribosomal RNA gene nucleotide sequence of bovine Theileria isolates (Korea and Japan) and Theileria buffeli (Marula, Kenya)

Small subunit ribosomal RNA (SSU rRNA) gene nucleotide sequences of bovine Theileria isolates from Korea (KLS and KCB) and Japan (JHS) were determined. The genes from each isolate were amplified by the polymerase chain reaction and the approximately 1.8 kb product cloned and sequenced by a modified dideoxynucleotide method. Overlapping gene segments produced with a series of primers were sequenced, resulting in a complete DNA sequence for both forward and reverse strands of the SSU rRNA genes of each isolate. SSU rRNA gene sequences (termed Type A) were identical among the bovine Theileria isolates from Korea and the isolate from Japan. A GenBank data library homology search showed the sequence to be the same as that listed as Theileria buffeli isolated from cattle in Marula, Kenya.

Nucleotide sequence heterogeneity in the small subunit ribosomal RNA gene variable (V4) region among and within geographic isolates of Theileria from cattle, elk and white-tailed deer

The phylogenetic relationships among fourteen isolates of benign Theileria spp. infecting cattle, elk and white-tailed deer were studied by nucleotide sequence comparisons of the variable (V4) region (200 nucleotides) of the small subunit ribosomal RNA gene. Included were six Korean bovine, one Japanese bovine, three North American bovine, and four North American cervine isolates. The SSU rRNA gene from each isolate was amplified, cloned, and the V4 region fragment sequenced. Seven different nucleotide sequence patterns were obtained and classified. Type A was identical to T. buffeli SSU rRNA gene sequence (GenBank Accession No. Z15106) and was found in Korean, Japanese, and North American bovine isolates. Type B was found in bovine isolates from Korea, Japan and North America. Type C was found only in the Korean bovine isolate from Chungnam. Type D was found in a Korean and in a North American bovine isolate. Type E was found in a bovine isolate from Cheju Island of Korea and a North American cervine (elk) isolate. Types F and G were found only in North American cervine isolates (both white-tailed deer and elk) and appear to represent a species separate from the bovine isolates. The presence of several sequence types observed in most of the bovine Theileria isolates may indicate mixed species (or subspecies) populations and/or multiple genotypes within a single species.

Biotin-labeled DNA probe in a PCR-based assay increases detection sensitivity for the equine hemoparasite Babesia caballi

A DNA probe from Babesia caballi (Bc1) was selected by antibody screening of a genomic library. The Bc1 probe hybridized specifically to B. caballi genomic DNA. A polymerase-chain-reaction-based assay for B. caballi DNA was developed from primers deduced from the probe nucleotide sequence. An amplified product of 1.6 kb was detected from as little as 500 fg B. caballi template DNA. Sensitivity increased 1000-fold when the biotin-labeled Bc1 probe was hybridized to the amplicons in a Southern blot.

Case report: field-acquired subclinical Babesia equi infection confirmed by in vitro culture

A horse with no prior clinical history of equine piroplasmosis tested negative for Babesia caballi and Babesia equi in the complement fixation test before importation into the United States from France. After 5 years in residence in the United States, the animal tested serologically positive for B. equi by the complement fixation test, the immunofluorescent antibody test, and Western blot analysis. The carrier status of the horse was confirmed by culture of B. equi parasites. In vitro culture offers an efficient and comparatively inexpensive method to determine the carrier status of horses suspected of harboring B. equi.

Culture isolation and partial characterization of a Babesia sp. from a North American elk (Cervus elaphus)

Three North American yearling elk (Cervus elaphus) died with clinical symptoms suggestive of babesiosis. Babesia sp. organisms similar in morphology to B. odocoilei of white-tailed deer (Odocoileus virginianus) were observed in Giemsa-stained blood films from one of the elk. Continuous cultures of the parasite were established. Antiserum raised against the elk Babesia sp. isolate was compared to B. odocoilei specific antiserum in an immunofluorescent antibody assay; we found evidence of differences in reactivity to several Babesia spp. isolated from wildlife and domestic ruminants. Cultured parasites from the elk were not infective to either intact or splenectomized Bos taurus steers.

Babesia equi erythrocytic stage continuously cultured in an enriched medium

Babesia equi was continuously cultured through 90 passages in an enriched chemically defined basal medium (HL-1) supplemented with 20% fetal bovine serum and serum replacement factors, including lipid-rich bovine serum albumin, bovine insulin, and human transferrin. Cryopreservation and subsequent recovery of B. equi were easily achieved. Inoculation of a splenectomized and an intact horse with cultured infected erythrocytes resulted in parasitemias and B. equi in vitro reisolation from both animals. In vitro forms of the parasite resembled in vivo forms. After establishment, parasitemias of 10-15% were commonly observed.

In vitro isolation and cultivation of a Babesia from an American woodland caribou (Rangifer tarandus caribou)

A Babesia species isolated from a captive caribou (Rangifer tarandus caribou) with clinical signs of babesiosis and a circulating parasitemia was cultured in vitro. Normal adult caribou erythrocytes supported the growth of the Babesia sp., as did erythrocytes from white-tailed deer (Odocoileus virginianus). Two basal media (M-199 and RPMI-1640) and a defined medium (HL-1) each supplemented with adult bovine serum were compared. The most favorable growth of the parasite occurred in HL-1 medium with 20% adult bovine serum. The morphology of this Babesia sp. isolate shared some characteristics with B. odocoilei and B. divergens.

Ultrastructural characteristics of Babesia odocoilei in vitro

Babesia odocoilei continuously cultured in white-tailed deer (Odocoileus virginianus) erythrocytes was examined by transmission and scanning electron microscopy. Merozoites, trophozoites, intermediate-stage forms, and dividing forms were observed. Merozoites possessed a single nucleus, inner membrane complex, rhoptries, free ribosomes, rough endoplasmic reticulum, and single membrane-bound vesicles. Trophozoites lacked an inner membrane complex and rhoptries. Intermediate stages were characterized by distinct segments of inner membrane complex. Dividing forms ranged from cells with an elongated nucleus to mature daughter cells joined by a ringlike structure. Babesia odocoilei was characterized by its close proximity to the erythrocyte membrane, membranous structures resembling feeding organelles, and reproduction via a method resembling budding sensu stricto.

In vitro growth of Babesia bovis in white-tailed deer (Odocoileus virginianus) erythrocytes

Babesia bovis cultured in bovine erythrocytes was passaged into white-tailed deer (Odocoileus virginianus) erythrocytes and medium containing either white-tailed deer serum or bovine serum. Deer erythrocytes supported the growth of the parasite only in the presence of bovine serum. Cryopreserved cultures were recovered successfully in white-tailed deer erythrocytes. By light and electron microscopy, B. bovis structure appeared similar in host cells of either species.

Culture confirmation of the carrier status of Babesia caballi-infected horses

Culture of horse blood for Babesia caballi identified four carrier horses among nine previously infected horses. Three of the carriers had no detectable parasitemias on stained blood smears, and sera from two carrier horses were complement fixation test negative. Three cultures were continuously cultivated. Cryopreserved fourth-passage B. caballi was successfully reestablished in vitro. Blood from a 10th horse previously subinoculated with blood from a suspected carrier was cultured, with negative results.

Isolation and in vitro cultivation of Babesia parasites from free-ranging desert bighorn sheep (Ovis canadensis nelsoni) and mule deer (Odocoileus hemionus) in California

Protozoal parasites of the genus Babesia were isolated for the first time from free-ranging desert bighorn sheep (Ovis canadensis nelsoni) and mule deer (Odocoileus hemionus) populations in California by in vitro culture of host blood. These naturally infected animals did not have microscopically detectable parasitemia at the time blood was collected for parasite cultivation. Three isolates of small Babesia parasites were cultured from different sample groups of bighorn sheep, and 2 isolates of large Babesia parasites were cultured from a group of bighorn sheep and a group of mule deer, respectively. The size and structure of the various forms of piroplasms from each isolate remained consistent throughout the period of cultivation. Statistical comparison of the sizes of the piroplasms among the isolates indicated that there were at least 2 distinct morphotypes. Four of the 5 isolates were maintained with continuous growth in cultures containing erythrocytes from uninfected donor bighorn sheep, mule deer, and domestic sheep. Cryopreservation or storage of cultures at 4 C for 7 days did not affect viability of the isolates. These results demonstrate the potential for use of in vitro cultivation methods for the isolation of Babesia parasites from free-ranging artiodactylids.

In vitro cultivation of a Babesia isolated from a white-tailed deer (Odocoileus virginianus)

Pyriforms and ring forms of Babesia odocoilei were detected in thin blood smears obtained from a white-tailed deer killed by a hunter in Anderson County, Texas. Erythrocytes from the deer were cultured and the parasites maintained through 8 serial subcultures during 1 mo. The parasite was successfully established in culture using Medium 199 supplemented with either 20% deer serum or 40% normal adult bovine serum. The highest parasitemia observed was 30% and more than 4 parasites per erythrocyte were often observed. Cultured B. odocoilei remained infective for a susceptible white-tailed deer.

Derivation of monoclonal antibodies against Brucella abortus antigens

In vivo immunization, fusion, antibody detection, and cryopreservation procedures for monoclonal antibody production against antigens of Brucella abortus are described. Splenocytes from BALB/c mice immunized with irradiated B. abortus S2308 were fused with Sp2/O-Ag14 myeloma cells and 61 hybridomas secreting anti-Brucella antibodies were cloned. Hybridoma antibody synthesis was detected effectively and most efficiently by enzyme-linked immunosorbent assays. Antibodies from clones of hybridoma A23 reacted with S19 and S2308 whole bacterial cells, while hybridoma B49 reacted primarily with alkali--treated lipopolysaccharides of S19, S1119.3 and S2308. Cryopreservation of clones had no major effect on antibody synthesis. The application of monoclonal anti-Brucella antibodies in the differential diagnosis of bovine brucellosis is discussed.

Ultrastructure of Babesia bovis sexual stages as observed in Boophilus microplus cell cultures

Propagation of Babesia bovis in a Boophilus microplus cell line resulted in the appearance of the sexual stage of the parasite normally found only within tick intestine. These sexual stages, which possessed spike-like projections containing microtubules, were present in the medium and within cultured cells. Other ultrastructural characteristics of this sexual stage are described.

A new tick cell line derived from Boophilus microplus

The Boophilus microplus IX tick cell line was developed from a primary embryonic cell culture derived from eggs six to nine days old. The cell line has been in culture since March 1979 and is currently maintained at 32 degrees C in medium consisting of equal parts of minimum essential medium an Leibovitz 15 medium supplemented with 20 per cent fetal bovine serum, 10 per cent tryptose phosphate broth and 0.1 per cent plasma albumin. A split ratio of 1:2 has been used for all subcultures and the cell line is now in its 26th passage. The cells are predominantly epithelial-like and of the male diploid chromosome number 21.