AAOS & ABOS Spine MCQs (Set 4): Trauma, Degenerative & Deformity | Board Prep

Halo fixation is the most rigid form of cervical orthosis, but complications can arise from improper placement of the initial halo ring. A relatively safe zone for anterior pin placement is located 1 cm above the orbital rim and superior to the lateral two thirds of the orbit. This position avoids the supraorbital and supratrochlear nerves and arteries over the medial one third of the orbit. The more lateral positions in the temporal fossa have very thin bone and can interfere with the muscles of mastication. Posterior pin site locations are less critical; positioning on the posterolateral aspect of the skull, diagonal to the contralateral anterior pins, is generally desirable. Botte MJ, Byrne TP, Abrams RA, et al: Halo skeletal fixation: Techniques of application and prevention of complications. J Am Acad Orthop Surg 1996;4:44-53.

The patient has lumbar spinal stenosis and the MRI scans reveal the pathology at L4-5, which is secondary to posterior disk bulging and hypertrophy and infolding of the ligamentum flavum, as well as degenerative facet arthrosis. The degree of spinal stenosis is moderate and his symptoms are positional in nature. Tadokoro and associates reported on a prospective study of 89 patients older than 70 years of age who underwent nonsurgical management for lumbar spinal stenosis. They found the prognosis to be relatively good with patients scoring at "excellent" or "good" for activities of daily living at final follow-up. However, they did note that patients with a complete block on myelography did not respond favorably to nonsurgical management. Amundsen and associates reported on a 10-year prospective study comparing surgical care to nonsurgical management. They concluded that, while the long-term results largely favored surgical treatment, more than half of the nonsurgically managed patients had a satisfactory outcome. They also concluded that a delay of surgery for some months did not worsen the prognosis. Therefore, their recommendation was for an initial primarily nonsurgical approach. Amundsen T, Weber H, Nordal HJ, et al: Lumbar spinal stenosis: Conservative or surgical management? A prospective 10-year study. Spine 2000;25:1424-1435. Hilibrand AS, Rand N: Degenerative lumbar stenosis: Diagnosis and management. J Am Acad Orthop Surg 1999;7:239-249.

The smallest pedicle isthmic width is at L1, whereas T12 has the largest pedicle width in the upper lumbar and lower thoracic spine. Although smaller in diameter than T12, both T10 and T11 have larger pedicle widths than L1.

Kondrashov and associates noted stable good outcomes at 4 years in 14 of 18 patients treated with X-STOP interspinous process decompression as defined as an improvement over preoperative Oswestry scores of 15 points or more. Similar results were seen after 1 year in a European study by Siddiqui and associates. Exclusion and inclusion criteria for these studies varied somewhat, but cauda equina syndrome was the only exclusion criteria listed in both studies. All of the other choices did not represent exclusion criteria in either study. Kondrashov DG, Hannibal M, Hsu KY, et al: Interspinous process decompression with the X-STOP device for lumbar spinal stenosis: A 4-year follow-up study. J Spinal Disord Tech 2006;19:323-327.

It has been traditionally taught that a left-sided approach to the anterior cervical spine is associated with a lower incidence of injury compared to the right-sided approach. This is due in part to the anatomic differences in the path the recurrent laryngeal nerve (RLN) takes on the right as compared to the left. Both nerves ascend in the tracheoesophageal groove after branching off the vagus nerve in the upper thorax. The left-sided RLN loops around the aortic arch and stays relatively medial as compared to the right-sided RLN which loops around the right subclavian artery and is somewhat more lateral at this point, and therefore is theoretically more vulnerable as it ascends toward the larynx before becoming protected in the tracheoesophageal groove. Furthermore, the variant of a nonrecurrent inferior laryngeal nerve branching directly off the vagus nerve at the level of the midcervical spine is much more common on the right than the left. Despite this reasoning, there has been no clinical evidence to suggest that laterality of approach for anterior cervical surgery makes any difference in the incidence of vocal cord paralysis. Furthermore, two recent studies have shown that the incidence of RLN injury and vocal cord paralysis is equal with either side of approach. Beutler WJ, Sweeney CA, Connolly PJ: Recurrent laryngeal nerve injury with anterior cervical spine surgery risk with laterality of surgical approach. Spine 2001;26:1337-1342.

The imaging studies show a fracture-dislocation. Surgical treatment of this injury consists of a decompression reduction, stabilization, and fusion. A posterolateral decompression can also be performed as necessary. An isolated anterior procedure in this type of injury is contraindicated. The anterior longitudinal ligament is most likely intact; therefore, an anterior procedure further destabilizes the spine. Reduction by an anterior approach would also be difficult. Nonsurgical management of the neurologic injury in this patient is not indicated. Theiss SM: Thoracolumbar and lumbar spine trauma, in Stannard JP, Schmidt AH, Kregor PJ (eds): Surgical Treatment of Orthopaedic Trauma. New York, NY, Thieme, 2007, pp 179-207.

The recently published SPORT trial verifies that surgical treatment of symptomatic disk herniations is associated with early and sustained pain relief. The trial also verifies that nonsurgical management is associated with improved symptoms as well. Nerve root injury, recurrent herniation, and diskitis are known complications of surgery, but all are less common than described above.

Clearance of the cervical spine can be difficult in the obtunded or unresponsive patient. Various trauma series have been reported to detect up to 95% of cervical fractures but only when ideal imaging views have been obtained, which is not often possible in the unresponsive or uncooperative patient. Passively performed cervical flexion-extension under live fluoroscopy has been suggested but is not without inherent risk in the potentially unstable cervical spine. CT of the cervical spine has gained acceptance for the evaluation of these patients given the excellent evaluation of the osseous anatomy and for the common availability in most emergency departments. Sanchez and associates, using a protocol to evaluate for cervical spine injuries after blunt trauma, were able to detect 99% of cervical fractures with 100% specificity. Chiu WC, Haan JM, Cushing BM, et al: Ligamentous injuries of the cervical spine in unreliable blunt trauma patients: Incidence, evaluation, and outcome. J Trauma 2001;50:457-463. Sanchez B, Waxman K, Jones T, et al: Cervical spine clearance in blunt trauma: Evaluation of a computed tomography-based protocol. J Trauma 2005;59:179-183.

When attempting a revision anterior cervical approach from the side opposite the original approach, it is important to evaluate the function of the vocal cords. If this evaluation reveals dysfunction of the vocal cord on the side of the original approach, then an approach on the contralateral side should not be attempted. Injury to the stellate ganglion, which causes a Horner's syndrome, should not preclude an approach on the contralateral side. While the side of the symptomatology can influence the surgeon's choice as to the side of an anterior approach, it does not preclude a certain approach. When approaching the lower cervical spine from the right side, the recurrent laryngeal nerve can cross the surgical field and should be preserved. Excessive intraoperative pressure on the esophagus can increase the incidence of dysphagia, but its incidence is no different with either approach. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 387-394.

The CT scans show a burst fracture that results from an axial load injury. The radiographic hallmark of a burst fracture is compression of the posterior cortex of the vertebral body with retropulsion of bone into the spinal canal. AP radiographs often show widening of the interpedicular distance with a fracture of the lamina. Theiss SM: Thoracolumbar and lumbar spine trauma, in Stannard JP, Schmidt AH, Kregor PJ (eds): Surgical Treatment of Orthopaedic Trauma. New York, NY, Thieme, 2007, pp 179-207.

In examining a traditional Muslim woman, a male physician should have another woman present, and the patient's husband, if possible. Only the affected limb or area needing examination should be exposed.

The hallmark of neurogenic shock is hypotension without tachycardia. It is associated most commonly with high cervical spinal cord injuries and results from loss of function of the sympathetic nervous system. Because the peripheral vasculature is dilated due to loss of its sympathetic tone, continued rapid administration of fluid corrects the hypotension and can quickly lead to fluid overload and congestive heart failure. Therefore, neurogenic shock is best treated by the use of pressors. Cardioversion or administration of antibiotics or systemic steroids is not appropriate treatment for this patient's hypotension. Spivak JM, Connolly PJ (eds): Orthopaedic Knowledge Update: Spine 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, pp 179-187.

Thoracic pedicles typically are angled 25 degrees medially at T1 so the starting point is more lateral. T2 angles about 15 degrees, and then the pedicles average about 5 to 7 degrees down to T10. At T11 and 12, the angulation is minimal. Weinstein L: Pediatric Spine Principles and Practice. New York, NY, Raven Press, 1994, pp 1659-1681.

The omohyoid muscle crosses the surgical field from inferior lateral to anterior superior traveling from the scapula to the hyoid bone and may need to be transected. The posterior digastric crosses the field as well but higher near C3-4. The other muscles run longitudinally. Chang U, Lee MC, Kim DH: Anterior approach to the midcervical spine, in Kim DH, Henn JS, Vaccaro AR, et al (eds): Surgical Anatomy and Techniques to the Spine. Philadelphia, PA, Saunders Elsevier, 2006, pp 45-56.

The annulus fibrosis has a multilayer lamellar architecture mode of type I collagen fibers. Each successive layer is oriented at 30 degrees to the horizontal in the opposite direction, leading to a "criss-cross" type pattern. This composition allows the annulus, which has the highest tensile modulus, to resist torsional, axial, and tensile loads.

When patients are compared at 5 years follow-up, there are no statistically significant differences between the two groups with respect to kyphosis, the degree of retropulsed bone resorption, pain and function levels, or the ability to return to work. Nonsurgical management of stable neurologically intact burst fractures has a very low incidence of complications. Wood K, Butterman G, Mehbod A, et al: Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit: A prospective, randomized study. J Bone Joint Surg Am 2003;85:773-781.

The MRI scans reveal advanced degenerative disk disease at L5-S1. Nonsurgical management has failed to provide relief and the patient is quite debilitated as a result of her back pain. Fritzell and associates demonstrated that in a well-informed and selected group of patients with severe low back pain, lumbar fusion can diminish pain and decrease disability more efficiently than commonly used nonsurgical treatments. In a recent updated Cochrane Review of surgery for degenerative lumbar spondylosis, it was noted that while Fritzell and associates appeared to provide strong evidence in favor of fusion, a more recent trial by Brox and associates demonstrated no difference between those patients undergoing lumbar fusion compared to those receiving cognitive intervention and exercise. The Cochrane Review suggests that this may reflect a difference between the control groups. Fritzell and associates compared lumbar fusion to standard 1990s "usual care," whereas Brox and associates compared lumbar fusion to a "modern rehabilitation program." Bear in mind that this patient is a certified athletic trainer and runs a hospital health fitness department; therefore, at least for purposes of this question, it can be assumed that she has participated in a "modern rehabilitation program." The Cochrane Review goes on to state that preliminary results of three small trials of intradiskal electrotherapy suggest that it is ineffective and that preliminary data from three trials of disk arthroplasty do not permit firm conclusions. Gibson JN, Waddell G: Surgery for degenerative lumbar spondylosis: Updated Cochrane Review. Spine 2005;30:2312-2320. Fritzell P, Hagg O, Wessberg P, et al: 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: A multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine 2001;26:2521-2532.

The MRI scan reveals a L4-L5 foraminal disk herniation originating from the L4-5 disk space that has migrated up into the foramen, compressing the left L4 nerve root. There is normal distribution of the roots in the cerebrospinal fluid, excluding arachnoiditis as a diagnosis, and disk herniation in this location would not result in cauda equina syndrome or myelopathy.

Intradiskal electrothermal therapy (IDET) initial clinical results were reported in 2000. The early case series were quite encouraging with reported therapeutic success rates of 60% to 80%. Early enthusiasm was high as IDET provided a nonsurgical treatment option for an otherwise complex and difficult clinical entity, chronic diskogenic low back pain. The actual mechanism of action was not well understood, and while the theoretic explanation made good sense, it did not hold up under laboratory testing. Soon clinical results from the field did not meet the high expectations set by the developers of the technique. Since those early case studies, a few level I evidence studies have been conducted, one by Freeman and associates and one by Pauza and associates. These randomized, placebo-controlled trials demonstrated no significant benefit of IDET over the placebo. Freeman BJ, Fraser RD, Cain CM, et al: A randomized, double-blind, controlled trial: Intradiscal electrothermal therapy versus placebo for the treatment of chronic discogenic low back pain. Spine 2005;30:2369-2377. Pauza KJ, Howell S, Dreyfuss P, et al: A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain. Spine J 2004;4:27-35.

Hypothenar atrophy is a nonspecific sign that can be seen in ulnar neuropathy, C8 radiculopathy, or even cervical myelopathy; however, the atrophy usually is not unilateral and includes other muscle groups. The Spurling test is an excellent method of eliciting cervical radicular pain but involves hyperextension and ipsilateral rotation of the cervical spine, resulting in nerve root compression by reducing the cross-sectional area of the ipsilateral neuroforamen. Tinel's sign at the levator scapulae, if present, is indicative of an upper cervical (C3 or C4) radiculopathy. A subluxable ulnar nerve at the cubital tunnel, while often asymptomatic, points toward cubital tunnel syndrome as an etiology for this patient's pain. The shoulder abduction relief (SAR) sign (relief of upper extremity pain with shoulder abduction) is virtually pathognomic of cervical radiculopathy because this maneuver results in relaxation of a compressed and/or inflamed cervical nerve root. The SAR sign is the converse analog of the straight leg raising sign in the lumbar examination for lumbar radiculopathy, as it relieves tension in the nerve root, thereby relieving symptoms. Ducker TB, Zeidman SM: Neurologic and functional evaluation, in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, pp 143-161. An HS: Clinical presentation of discogenic neck pain, radiculopathy, and myelopathy, in Clark CR (ed): The Cervical Spine, ed 3. Philadelphia, PA, Lippincott Raven, 1998, pp 755-764.

The patient's neurologic examination is consistent with a C7 radiculopathy on the right side. In a patient with this symptom complex in the absence of trauma, a cervical disk herniation is the most common etiology for a C7 radiculopathy. There are eight cervical nerve roots and the C7 nerve exits at the C6-7 disk space and is most frequently impinged by a disk herniation at this level. Houten JK, Errico TJ: Cervical spondylotic myelopathy and radiculopathy: Natural history and clinical presentation, in Clark CR (ed): The Cervical Spine, ed 4. Philadelphia, PA, Lippincott Williams & Wilkins, 2005, pp 985-990.

Patient positioning that results in local nerve compression, plexus traction, or improper neck alignment is the most common nonanesthetic-related cause of changes in intraoperative neurophysiologic monitoring data during spinal surgery. Jones SC, Fernau R, Woeltjen BL: Use of somatosensory evoked potentials to detect peripheral ischemia and potential injury resulting from positioning of the surgical patient: Case reports and discussion. Spine J 2004;4:360-362.

The surgeon perforated the anterior longitudinal ligament and injured the common iliac artery. Bingol and associates described injuries to the vascular structures during lumbar disk surgery. The common iliac artery was most commonly affected and constituted 76.9% of injuries.

In the absence of a cauda equina syndrome or progressive weakness, the best indication for surgical management is refractory radicular pain. Surgical decision-making should not be based on the size of the herniation. Large extruded herniations tend to resolve more predictably than smaller herniations. Stable motor weakness and numbness resolve similarly in both surgical and nonsurgical management, although surgery hastens the process. When intractable radicular pain is the strict indication for surgery, surgical intervention provides substantial and more rapid pain relief than nonsurgical care. Rhee JM, Schaufele M, Abdu WA: Radiculopathy and the herniated lumbar disc: Controversies regarding pathophysiology and management. J Bone Joint Surg Am 2006;88:2070-2080.

A thoracotomy in an adult with idiopathic scoliosis causes a reduction in pulmonary function that often does not return to preoperative levels. What pulmonary function that does recover, recovers over many months. Long-term improvement in pulmonary function, compared to preoperative function, is rarely seen. This should be considered in planning surgical intervention in adults with scoliosis. Graham EJ, Lenke LG, Lowe TG, et al: Prospective pulmonary function evaluation following open thoracotomy for anterior spinal fusion in adolescent idiopathic scoliosis. Spine 2000;25:2319-2325.