An unusual course of the vertebral artery posterior to the nerve root in the inter-transverse space: a cadaveric study.

BACKGROUND: The V2 segment of the vertebral artery is very vulnerable to injury during cervical spine surgery. The incidence of vertebral artery injury during anterior cervical spine procedures is reported to be 0.22-2.77 %. This is partially due to its variable course while running in the transverse foramens of the cervical vertebrae. CASE PRESENTATION: The course of the vertebral artery in the dissected cadaver of a 79 year old female is presented. Dissection of the left vertebral artery showed that the 5(th) nerve root passes in front of the vertebral artery in the 4(th) intertransverse space. Further exploration showed that although vertebral artery at first passed at the back of the nerve root it curved downwards again and after passing underneath the 5(th) nerve root entered the 4(th) vertebral body. After making a loop in the left half of the vertebrae, vertebral artery ran anterior to the nerve root and after entering the 4(th) transverse foramen showed up in the 3(rd) intertransverse space. The shortest distance of the vertebral artery to the midline at the 4(th) vertebrae level was 4.78 mm. CONCLUSIONS: To our knowledge this case is the first report of a nerve root lying anterior to the vertebral artery in the intertransverse space of the cervical spine. Additionally vertebral artery has never been reported to be so close to the midline. This report signifies the importance of obtaining MRI or contrast enhanced CT scan prior to any cervical spine surgery in the vicinity of the vertebral artery including corpectomies and also careful approach to the intertransverse space during the operation.

A safe approach to explore/identify the V(2) segment of the vertebral artery during anterior approaches to cervical spine and/or arterial repairs: anatomical study.

OBJECT: The purpose of this study was to find a landmark according to which the surgeon can dissect the cervical spine safely, with the lowest possibility of damaging the vertebral artery (VA) during anterior approaches to the cervical spine or the VA. METHODS: The "safe zone" for each level of the cervical spine was described as an area where the surgeon can start from the midline in that zone and dissect the soft tissue laterally to end up on the transverse process and cross the VA while still on the transverse process. In other words, safe zone signifies the narrowest width of the transverse process at each level. In such an approach, the VA is protected from the inadvertent deep penetration of the instruments by the transverse process. The surgical safe zone for each level was the common area among at least 95% of the safe zones for that level. For the purpose of defining the upper and lower borders of the safe zone for each level, the line passing from the upper vertebral border perpendicular to the midline (upper vertebral border line) was used as a reference. Cervical spines of 64 formalin-fixed cadavers were dissected. The soft tissue in front of the transverse process and intertransverse space was removed. Digital pictures of the specimens were taken before and after removal of the transverse processes, and the distance to the upper and lower border of the safe zone from the upper vertebral border line was measured on the digital pictures with Image J software. The VA diameter and distance from the midline at each level were also measured. To compare the means, the authors used t-test and ANOVA. RESULTS: The surgical safe zone lies between 1 mm above and 1 mm below the upper vertebral border at the fourth vertebra, 2 mm above and 1 mm below the upper vertebral border at the fifth vertebra, and 1 mm above and 2 mm below the upper vertebral border of the sixth vertebra. The VA was observed to be tortuous in 13% of the intertransverse spaces. There is a positive association between disc degeneration and tortuosity of the VA at each level (p < 0.001). The artery becomes closer to the midline (p < 0.001) and moves posteriorly during its ascent. CONCLUSIONS: Dissection of the soft tissue off the bone along the surgical safe zone and removal of the transverse process afterward can be a practical and safe approach to avoid artery lacerations. The findings in the present study can be used in anterior approaches to the cervical spine, especially when the tortuosity of the artery mandates exposure of the VA prior to uncinate process resection, tumor excision, or VA repair.

Spontaneous cervical epidural hematoma masquerading as an abscess on magnetic resonance imaging scan.

OBJECTIVE: The aims of the study are to describe a case of spontaneous spinal epidural hematoma (SSEH) without any predisposing factors and magnetic resonance imaging (MRI) features of epidural abscess and to highlight the importance of high clinical suspicion. CLINICAL FEATURES: A 75-year-old male presented to the emergency department after a severe neck pain. He progressively showed sensory and upper motor signs on the left side of the body. The MRI scans were suggestive of cervical epidural abscess with peripheral enhancement of the lesion. INTERVENTIONS AND OUTCOMES: He underwent a multiple level (C3-T1) laminectomy when he was found to have an SSEH. There has been no history of trauma or other predisposing factor, and presence of arteriovenous malformation was ruled out by MR angiography. CONCLUSIONS: The MRI features of SSEH may be misleading and mimic other spinal lesions such as abscess. Presence of tapering superior and inferior margins, spotty Gadolinium enhancement in the mass, along with abrupt clinical onset of pain and neurologic deficit, should raise the suspicion toward epidural hematoma. Enhancement in the hyperacute stage of the hematoma itself might indicate continued bleeding and, in the case of deteriorating neurologic status, will necessitate decompression.

A comparison of the torsional stiffness of the lumbar spine in flexion and extension.

OBJECTIVE: The main mechanism of injury to the spine is torsion especially when coupled with compression. In this study, the in vitro torsional stiffness of the lumbar spine segments is compared in flexion and extension positions by cyclic and failure testing. METHODS: Fifteen lumbar spines were sectioned from fresh cadavers into 15 L2/3 and 15 L45 motion segments. Each vertebral segment was then potted superiorly and inferiorly in polymethylmethacrylate, effectively creating a bone-disk-bone construct. The potted spinal segments were mounted in a mechanical testing system, preloaded in compression to 300 N, and axially rotated to 3 degrees in both directions at a load rate of 1 degrees /s. This was done over 3 cycles for each motion segment in the flexion and extension positions. Each specimen was then tested to torsional failure in either flexion or extension. Stiffness, torque, and energy were determined from cyclic and failure testing. RESULTS: The results showed that in all cases of cyclic testing, the higher segment extension resulted in higher torsional stiffness. In relative extension, the lumbar specimens were stiffer, generated higher torque values, and generally absorbed more energy than the relative flexion condition. There were no differences found in loading direction or failure testing. CONCLUSIONS: Increasing the effective torsional stiffness of the lumbar spine in extension could provide a protective mechanism against interverbral disk injury. Restoration of segmental extension through increasing the lumbar lordosis may decrease the strain and reinjury of the joints, which can help reduce the extent of pain in the lumbar spine.

Percutaneous spine biopsy: a meta-analysis.

BACKGROUND: Percutaneous spine biopsy has widely replaced open biopsy. We conducted a meta-analysis to evaluate the effect of the inner diameter of the biopsy needle and the method of imaging guidance on the adequacy and accuracy of tissue samples and to evaluate the complication rates associated with the different needle diameters and imaging guidance methods. METHODS: We searched MEDLINE for studies that evaluated either the adequacy (whether or not a diagnosis could be made on the basis of pathologic examination) or the accuracy (whether or not the primary diagnosis was correct) of samples obtained by means of percutaneous spine biopsy. These articles and their relevant references subsequently were reviewed twice and were evaluated against the inclusion criteria, yielding twenty-five studies. The inclusion criterion was the use of a biopsy instrument (a fine needle or trephine with an identifiable inner diameter) under the guidance of imaging (fluoroscopy or computed tomography) for the evaluation of an identified spine lesion, with the report of either adequacy or accuracy. Meta-analysis with use of the random-effects model was used to analyze the data. RESULTS: The adequacy, accuracy, and complication rates increased with the inner diameter of the needles, but, with the numbers available, only the complication rate increased significantly (p = 0.01). Although the use of a computed tomography scan slightly increased the adequacy and accuracy of the samples, these increases were not significant. The complication rate associated with the use of computed tomography was 3.3%, compared with 5.3% for fluoroscopy. CONCLUSIONS: As the outcomes associated with computed tomography were not significantly different from those associated with fluoroscopy, the decision to use one or the other requires the consideration of other factors, such as the type, level, and vertebral location of the lesion as well as the expertise of the physician. In situations in which the use of a needle with a small inner diameter is highly effective (for example, in cases of metastatic lesions), the clinician should first consider using a needle with a smaller inner diameter to obtain the biopsy specimen because of the higher complication rate associated with large-bore needles. However, in cases of sclerotic lesions, in which obtaining an adequate sample can be difficult, the use of a needle with a larger inner diameter is desirable.

Bilateral isthmic L3 spondylolisthesis in an adult female.

OBJECTIVE: The purpose of this study is to describe an incidental finding of bilateral isthmic L3 spondylolysis in an adult female. CLINICAL FEATURES: A 26-year-old woman with sickle cell anemia was involved in a motor vehicle accident. Lumbar radiographs were reported normal. Computed tomography scan showed bilateral L3 spondylolysis of the pars interarticularis. INTERVENTIONS AND OUTCOMES: On the basis of the normal results of physical and neurologic examinations, the spondylolysis was considered to be an incidental finding. CONCLUSIONS: L3 spondylolysis is described very rarely in the literature. According to the unique features of L3 in the lumbar spine, which include its relatively horizontal position and its equal anterior and posterior diameters, we suggest that mechanical shearing forces may be less effective in causing spondylolysis in this area. This case is more suggestive of congenital and genetic causes as the contributing factors of spondylolysis.

Case report: bilateral slipped capital femoral epiphyses and hormone replacement.

A 24-year-old woman presented with an 11-year history of bilateral hip pain. Radiographs of the hips revealed severe bilateral slipped upper femoral epiphyses; the left side was more severely slipped than the right. While moving the hips under fluoroscopy we observed motion at the physes and reproduced the patient's pain; the motion confirmed the diagnosis of chronic slipped capital femoral epiphysis. Endocrinology tests showed hypothyroidism. After 1 year of thyroxin therapy, the patient's pain subsided and radiographs of the hips showed fusion of the physes. This case emphasizes the importance of screening for an endocrine disorder in patients with slipped capital femoral epiphysis particularly in adults and shows fusion can occur once the underlying endocrine abnormality is treated.

The prevalence of wrong level surgery among spine surgeons.

STUDY DESIGN: A questionnaire study. OBJECTIVE: To evaluate the prevalence of wrong level surgery among spine surgeons and their use of preventive measures to avoid its occurrence. SUMMARY OF BACKGROUND DATA: Wrong site surgery fails to improve the patient's symptoms and has medical, emotional, social, and legal implications. Organizations such as the North American Spine Society and the Joint Commission on Accreditation of Healthcare Organizations have established guidelines to prevent wrong site surgery. Spine surgeons' compliance with these guidelines and the prevalence of wrong-level spine surgery have not been investigated previously. METHODS: All members of the American Academy of Neurologic Surgeons (n = 3505) were sent an anonymous, 30-question survey with a self-addressed stamped envelope. RESULTS: A total of 415 (12%) surgeons responded. Sixty-four surgeons (15%) reported that, at least once, they had prepared the incorrect spine level, but noticed the mistake before making the incision. Two hundred seven (50%) reported that they had done 1 or more wrong level surgeries during their career. From an estimated 1,300,000 spine procedures, 418 wrong level spine operations had been performed, with a prevalence of 1 in 3110 procedures. The majority of the incorrect level procedures were performed on the lumbar region (71%), followed by the cervical (21%), and the thoracic (8%) regions. One wrong level surgery led to permanent disability, and 73 cases resulted in legal action or monetary settlement to the patient (17%). CONCLUSION: There is a high prevalence of wrong level surgery among spine surgeons; 1 of every 2 spine surgeons may perform a wrong level surgery during his or her career. Although all spine surgeons surveyed report using at least 1 preventive action, the following measures are highly recommended but inconsistently adopted: direct preoperative communication with the patient by the surgeon, marking of the intended site, and the use of intraoperative verification radiograph.

Esophageal perforation with a locking screw: a case report and review of the literature.

STUDY DESIGN: A case report with a review of the literature. OBJECTIVES: Anterior cervical spine surgery (ACS) has received widespread acceptance, and as a result, a variety of complications have been reported. Several cases of esophageal complications, arising from the use of various implants and grafts, have been described. The purpose of this article is to provide insight into the clinical presentation, diagnosis, types of involved implants, and the treatment of this entity. SUMMARY OF BACKGROUND DATA: Previous reports of esophageal complications (esophageal perforation, diverticula, and stricture) after ACS are reviewed. METHODS: Retrospective case study and literature review. RESULTS: Redundant locking screws should be removed due to the potential for extrusion into the esophagus. CONCLUSIONS: Regular, long-term follow-up of the patient undergoing anterior spine surgery is crucial. The wide range of possible complications mandates thorough workup. Early surgical treatment is imperative in the majority of esophageal complications.

Lumbar synovial joint hematoma in a patient on anticoagulation treatment.

STUDY DESIGN: Case report. OBJECTIVE: To describe a case of spinal epidural hematoma arising from the synovial joint due to anticoagulation therapy. SUMMARY OF BACKGROUND DATA: Spontaneous spinal epidural hematoma is a rarity in the literature with a variety of etiologies. In 1 study, it was reported to originate from a synovial joint due to osteoarthritis of the joint. METHODS: A case of hematoma of the lumber synovial joint is presented. RESULTS: A 67-year-old man who was on anticoagulation therapy presented with progressive neurologic symptoms in the right lower limb. Magnetic resonance imaging scan revealed what was thought to be a L4-L5 synovial joint cyst. During surgery, it was proven to be an epidural hematoma originating from the synovial joint. Microscopic examination confirmed the diagnosis and excluded the possibility of spinal synovial cyst. After spinal decompression, neurologic symptoms improved completely in 2 weeks. CONCLUSIONS: This is the first report of a synovial cyst hematoma due to anticoagulation therapy. Its magnetic resonance imaging features can be similar to synovial cyst, especially when it is hemorrhagic. Spinal decompression was the definitive treatment.