Symptomatic TDHs account for only 0.15% 1.8% Surgical management of multiple thoracic disc herniations via a transfacet approach: a report of 15 cases

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1 J Neurosurg Spine 15:76 81, 2011 Surgical management of multiple thoracic disc herniations via a transfacet approach: a report of 15 cases Clinical article Paul M. Arnold, M.D., 1 Philip L. Johnson, M.D., 2 and Karen K. Anderson, B.S. 1 Departments of 1 Neurosurgery and 2 Radiology, University of Kansas Medical Center, Kansas City, Kansas Object. Symptomatic thoracic disc herniations (TDHs) are rare, and multiple TDHs account for an even smaller percentage of symptomatic herniated discs. Most TDHs are found in the lower thoracic spine, with more than 75% occurring below T-8. The authors report a series of 15 patients with multiple symptomatic TDHs treated with a modified transfacet approach. Methods. Fifteen patients (9 women and 6 men) with a total of 32 symptomatic TDHs were treated surgically at the authors institution between 1994 and The average patient age was 51.1 years. Thirteen patients had 2-level herniation and 2 patients had 3-level disease. The most commonly involved level was T7 8 (10 herniations), followed by T6 7 and T8 9 (6 herniations each). All patients had long-standing myelopathic and/or radicular complaints at the time of pentation. Each disc that exhibited radiographically confirmed compsion of the spinal cord or nerve root was considered for ection. Only patients with lateral disc herniations were considered for the modified transfacet approach; patients with a centrally herniated disc underwent ventral or ventral-lateral procedu. The average follow-up time was 30 months. Results. All patients had successful ection of their herniated discs. All patients with preoperative weakness demonstrated improved strength, and 11 of 12 patients with preoperative pain showed improvement in pain. Sensory loss was less consistently improved. The 2 patients who underwent posterior fixation and fusion achieved radiographically confirmed fusion by the 1-year follow-up. Nine of 10 patients who were working returned to their jobs. Eleven of 12 patients with preoperative back or radicular pain had drastic or complete pain olution; 1 patient had no change in pain. All 7 patients with preoperative ambulatory difficulty had postoperative gait improvement. Complications were minimal. Conclusions. Multiple symptomatic herniated thoracic discs are rare causes of pain and disability, but should be treated surgically because good outcomes can be achieved with acceptably low morbidity. (DOI: / SPINE10642) Key Words multiple thoracic disc herniation multilevel disc herniation noncontiguous disc herniation discectomy posterior fixation and fusion modified transfacet approach Symptomatic TDHs account for only 0.15% 1.8% of all disc herniations that are treated surgically. 11,18,19,27 29 Even less common are operations for multiple symptomatic herniated thoracic discs; fewer than 35 cases have been reported in the English literature in the last 56 years. 1,2,4,6,7,11 14,18 20,23,24,28,29,33 The rarity of these lesions and their chronic pentation can make their management challenging. Diagnosis is often delayed, and disc ection is technically difficult. However, new techniques in CT and MR imaging have made diagnosis easier. Several authors have reported good ults with thoracoscopic ection of thoracic discs, despite a steep learning curve. 25,26,34 Transpedicular, lateral, and anterior discectomy approaches have been developed and perfected, each with more favorable outcomes than the initially described Abbreviations used in this paper: ASIA = American Spinal Injury Association; TDH = thoracic disc herniation. laminectomy approach. We report our experience with 15 patients who pented with multiple symptomatic thoracic herniated discs, and who were treated surgically via a modified transfacet approach. Methods Patient Population Fifteen patients with a total of 32 symptomatic TDHs were treated surgically at our institution between 1994 and During this same time period, 82 patients underwent surgery for single TDHs. There were 9 women and 6 men, and the average patient age was 51.1 years (range years). Thirteen patients had a 2-level herniation and 2 patients had 3-level disease. The most com- This article contains some figu that are displayed in color on line but in black and white in the print edition. 76 J Neurosurg: Spine / Volume 15 / July 2011

2 Transfacet approach for multiple thoracic disc herniations monly involved level was T7 8 (10 herniations), followed by T6 7 and T8 9 (6 herniations each) (Table 1, Fig. 1). All disc herniations in each patient were unilateral. All patients had long-standing myelopathic and/or radicular complaints at the time of pentation. Penting symptoms varied, but included back pain, weakness and numbness in lower extremities, and decreased ability to walk. Each disc that exhibited radiographically confirmed compsion (deformation or shape alteration) of the spinal cord or nerve root was considered for ection. Each patient underwent MR imaging and/ or CT myelography, which confirmed thecal sac compsion prior to surgery (Fig. 2). Only patients with lateral disc herniations were considered for the modified transfacet approach; patients with a centrally herniated disc underwent ventral or ventral-lateral procedu. During the same time period, 7 patients with single-level herniated thoracic discs were treated with a modified transfacet approach. Eleven patients required a ventral approach for ection of centrally herniated or calcified discs. One patient with 2 central herniated discs also underwent a ventral procedure. If there was a question whether the disc exhibited significant calcification, a CT or CT myelogram was obtained. If significant calcification existed, an anterior procedure was chosen. Patients were seen at 3-, 6-, 12-, 24-, and 36-month intervals postoperatively, and the average follow-up time was 30 months. Surgical Technique Patients with 2-level disease underwent discectomy only via a modified transfacet approach. The appropriate disc level is determined with intraoperative radiographic studies. Using a posterior midline incision and unilateral subperiosteal exposure, the facet joint ipsilateral to the side of the symptomatic herniation is identified and removed, using a combination of rongeurs, Kerrison devices, and high-speed drills. A hemilaminectomy is also performed, which allows visualization of the lateral aspect of the spinal cord. The disc is found directly underneath the ected facet joint. The disc is opened with a blade, and then removed with a pituitary rongeur. The last bit of disc can be pushed downward into the disc space with a downwardangled curette. Once the lateral portion of the disc is removed, the more midline fragments can be retrieved, until the nerve root and the spinal cord are decompsed. Adequate decompsion of the spinal cord can be assessed by placing a right-angled hook or Woodson instrument in the ventral epidural space. These maneuvers allow for disc ection through a limited midline incision, without the need for removal of any ribs, transverse processes, or pedicles, as in the lateral extracavitary approach. Because of the potential risk of kyphosis and instability, patients with disease at 3 levels underwent multiple discectomies via the same approach; their spines were stabilized with posterior fixation and fusion. Results All patients had successful ection of their herniated discs. All patients in our series had laterally herniated discs. More centrally located discs were difficult to ect, and other approaches may be more appropriate for this pathological entity. The 2 patients who underwent posterior fixation and fusion achieved radiographically confirmed fusion by the 1-year follow-up visit. Postoperative radiographic studies were not routinely obtained in the other patients. Nine of 10 patients who were working returned to their jobs. Eleven of 12 patients with preoperative back Fig. 1. Bar graph showing the number of disc herniations at each thoracic spine level. J Neurosurg: Spine / Volume 15 / July

3 P. M. Arnold, P. L. Johnson, and K. K. Anderson Fig. 2. A: Midline sagittal T2-weighted MR imaging study revealing multiple thoracic herniated discs. The discs are laterally herniated. B and C: Axial MR imaging studies confirming that 2 of these discs were compsing the spinal cord. or radicular pain had drastic or complete pain olution; 1 patient had no change in pain. All 7 patients with lowerextremity weakness (ASIA D) became normal (ASIA E). Only 2 of 15 patients had complications. One patient developed a postoperative wound infection, which olved with local wound care and antibiotic therapy; however, that patient had continued complaints of pain and did not return to work. The second patient developed transient weakness in the leg, which olved with no further complications, and that patient returned to work. There were no hardware complications. No patient in the series required any further surgery on the thoracic spine. Discussion A TDH is a rare cause of symptomatic spine disease, repenting only 0.1% 4.5% of all disc herniations, 8,18,19,28 and only 0.25% 0.75% of all symptomatic disc herniations. 11,19,27,29 Of all surgically treated disc herniations, this type repents only between 0.15% and 1.8%; 11,18,19,27 29 TDHs account for approximately 5 of every 1000 disc herniations. 10 This disease affects males and females equally, and is more common between the 3rd and 6th decades, 4,7,27 with a peak in the 4th decade of life. 4,8,19 Although TDHs have been reported at every level, 75% occur below T-8, with T11 12 being the most common site due to greater spinal mobility and weakness of the posterior longitudinal ligament. 7,11,18,19,27 The most commonly involved level in our study was T7 8, followed by T6 7 and T8 9. Central protrusions are the most common type of herniation in the thoracic spine 9 ; all patients in our series had lateral herniations. Multiple TDHs are far rarer than single-level disease. The first case of multiple TDH was reported by Svien and Karavitis in 1954, 32 and fewer than 35 cases have been reported in the English literature in the last 56 years. 1,2, 4,6,7,11 14,18 20,23,24,28,29,33 Most authors agree that disc herniation is due to a combination of factors, 24 including weakness of the posterior longitudinal ligament and the greater mobility of the lower thoracic spine. 7,18,19 Only 33% 50% of patients with symptomatic disease report a history of trauma. 11,27 Because the narrow thoracic spinal canal allows little room for space-occupying lesions, symptomatic TDHs must be treated quickly. Diagnosis and management of multiple TDHs can be challenging. It can be difficult to differentiate multiple TDHs from other thoracic extradural masses, 12 and neurological findings alone are inadequate to determine which of the herniated thoracic discs is causing symptoms. 19 More than 70% of patients with TDH are asymptomatic. 11 Symptom onset does not follow a characteristic pattern, and the clinical pentation can be extremely varied. 2,6,11,18 Patients with multiple TDHs pent similarly to patients with a single lesion; with pain, radiculopathy, or myelopathy. Due to the vague nature of these complaints and the slow progsion of symptoms, this condition is often misdiagnosed or the diagnosis is often delayed by months or years. 11,19 22,27 The clinical manifestation is not strongly associated with the position of the herniated disc, its level, composition, or size. 11,19,27 A TDH rarely pents with the severity of radiculopathic pain that is the hallmark of lumbar disc herniation. Penting pain can be either localized or radiating, and sensory deficits can take some time to appear; occasionally they are subclinical. There have been case reports of TDHs penting with flank pain, chest pain, chronic pain, chronic nausea and abdominal pain, acutely progsing paraplegia, and symptoms mimicking acute lumbar disease. MR imaging is now the modality of choice for the thoracic spine because it has improved the clinician s ability to identify TDH correctly, 10,11 often before the appearance of neurological symptoms. 7 Conservative treatment for multiple TDHs is ineffective. 11 Surgical intervention alone is considered to be the treatment of choice for symptomatic TDH, especially for patients with myelopathy. 6,7,11,13,15,18,19,21,22,29 Resection of symptomatic lesions is often technically demanding. The goals of surgical treatment are the decompsion of the spinal cord and/or nerve root, the prevention or correction of spinal instability and deformity, and prevention of the recurrence of disc herniation, 8 thereby alleviating patients pain and improving their quality of life as well as their neurological status, all while limiting morbidity. 8 As detailed 20 years later by Müller, 17 Antoni and Elsburg performed the first thoracic discectomy in 1931, via a posterior laminectomy approach. Unfortunately, this approach proved to be unsuccessful; it was associated with unacceptably high rates of morbidity and a low incidence 78 J Neurosurg: Spine / Volume 15 / July 2011

4 Transfacet approach for multiple thoracic disc herniations TABLE 1: Characteristics of patients with multiple thoracic herniated nuclei pulposi* Case No. Age (yrs), Sex Level Penting Sx Physical Exam Op Technique Postop Exam Length of FU Period Return to Work Complications 1 59, F T7 8, T8 9 BP radiating into rt LE decreased sensation in rt LE; no evidence of myelopathy T7 8, T8 9 discectomies motor 5/5; sensory exam WNL; reflexes , F T7 8, T8 9 BP & LE pain & numbness bilat decreased LE sensation T7 8, T8 9 discectomies motor 5/5; sensory exam WNL; pain 3 69, F T7 8, T11 12 spasticity, weakness, radicular pain 4 51, M T5 6, T7 8 decreased ability to walk, radicular mid-bp 5 79, F T5 6, T6 7, T7 8 BP, decreased ability to walk 6 62, M T7 8, T8 9 LE numbness, decreased LE strength decreased LE sensation, hyperreflexia, LE weakness 4/5 (ASIA D) decreased gait, LE sensory loss, myelopathy, increased reflexes, LE weakness 4/5, bilat LE pain decreased strength, decreased LE sensation, hyperreflexia; LE weakness 4/5 7 43, F T6 7, T7 8 BP thoracic radiculopathy; hyperreflexia 8 45, F T5 6, T6 7, T7 8 BP & lat chest pain, pathesias in BLEs 9 34, M T6 7, T7 8 thigh & LE numbness, LE pain 10 51, F T5 6, T6 7 mid-bp, LE pain & numbness 11 39, F T8 9, T9 10 mid-bp & LE pain & weakness, decreased ability to walk 12 51, M T8 9, T9 10 LE numbness, decreased LE sensation T7 8, T11 12 discectomies motor 5/5; sensation WNL; reflexes 2+ T5 6, T7 8 discectomies motor 4+/5; reflexes 3/4; NC in sensory exam; NC in pain T5 6, T6 7, T7 8 discectomies; T4 8 TP fusion w/ autograft & fixation motor 4+/5; sensory exam WNL; reflexes 3/4; pain LE weakness 4/5 T7 8, T8 9 discectomies motor 5/5; sensory exam WNL; reflexes 2+ thoracic radiculopathy T5 8 discectomies w/ T5 8 interbody fusion w/ autograft T6 7, T7 8 discectomies motor 5/5; reflexes 3+; sensory WNL; pain motor 5/5; sensory WNL; hyperreflexia, clonus T6 7, T7 8 discectomies motor 5/5; reflexes 3+; sensory improved; pain hyperreflexia T5 6, T6 7 discectomies motor 5/5; reflexes 2+; sensory WNL; pain hyperreflexia, thoracic myeloradiculopathy; LE weakness hyperreflexia, decreased LE sensation; thoracic myeloradiculopathy T8 9, T9 10 discectomies T8 9, T9 10 discectomies 32 mos; neuro exam normal 38 mos; normal exam, pain 52 mos; increased strength & balance (ASIA E) 49 mos; continued pain, increased ability to walk, NC in spasticity 40 mos; pain, increased ambulation 38 mos; increased strength (5/5) does not work does not work none none retired none no wound infection retired none 24 mos; pain 31 mos; pain does not work 14 mos; pain, numbness 18 mos; pain, numbness 21 mos; pain, increased LE strength none (5/5) 24 mos; Sx (continued) J Neurosurg: Spine / Volume 15 / July

5 P. M. Arnold, P. L. Johnson, and K. K. Anderson TABLE 1: Characteristics of patients with multiple thoracic herniated nuclei pulposi* (continued) Return to Work Complications Age (yrs), Sex Level Penting Sx Physical Exam Op Technique Postop Exam Length of FU Period Case No. 26 mos; good strength (5/5); Sx T8 9, T9 10 discectomies 13 55, F T8 9, T9 10 mid-bp thoracic radiculopathy, hyperreflexia yes transient weakness in LE; 24 mos; pain, LE strength increased (5/5); NC in gait T6 7, T7 8 discectomies reflexes 3+; pain 14 46, M T6 7, T7 8 BP, LE weakness decreased sensation below T-7, hyperreflexia; thoracic radiculopathy 12 mos; pain thoracic radiculopathy T10 11, T12 L1 discectomies low BP radiating to hip & bilat LE 15 47, M T10 11, T12 L1 * BP = back pain; FU = follow-up; LE = lower extremity; NC = no change; neuro = neurological; = olved; TP = transverse process; WNL = within normal limits. of pain reduction. Since that time, MR imaging and CT myelography have made diagnosis easier, and advances in surgical techniques have reduced the risk associated with thoracic disc removal. Transpedicular, transfacet pediclesparing, lateral extracavitary, and transthoracic approaches have been developed, with more favorable outcomes and better ults. More recently, thoracoscopic and minimally invasive techniques for thoracic disc ection, such as posterior and posterolateral endoscopic discectomy, have also been described. Compared with the strictly posterior laminectomy, ults of the newer surgical approaches demonstrate significant improvements in pain relief, neurological outcomes, and postoperative spinal stability. 5 Surgical treatment for TDH is indicated by severe or progsive myelopathy 3 as well as persistent axial back pain, and intractable radiculopathy. 5,8,16,30 Because of limitations to the anterior transthoracic procedu, posterior-based approaches are being reviewed again for treatment of lateral or paracentral TDH; in particular, the transpedicular and transfacet pedicle-sparing approaches offer more direct exposure. 8 Stillerman et al. 31 provided the first description of the transfacet pedicle-sparing approach, which is considered an excellent approach for lateral soft-disc herniations. 5 Improvement in postoperative spinal stability and back pain are thought to be achieved by sparing the pedicle and limiting dissection of soft tissue. 5 Stillerman et al. listed advantages and disadvantages of the approach. The advantages are as follows: 1) a smaller incision; 2) shorter operative time; 3) less blood loss; 4) less bone removal; and 5) less soft-tissue disruption as well as shorter hospital stays and less time off work. The disadvantages are as follows: 1) more difficulty in performing the microdiscectomy in larger patients due to the limited skin incision; 2) more difficulty in removing centrally located herniated discs without the use of specially designed instruments; and 3) more difficulty in evaluating the extent of decompsion after the microdiscectomy. Ohnishi et al. 18 described the surgical outcome in 12 patients with multiple TDHs treated by anterior decompsion and rib graft fusion via a transthoracic approach. The symptoms varied, but included back pain, sensory changes, weakness in both lower limbs, and urinary symptoms. Clinical outcomes were excellent in 2 patients, good in 2, fair in 6, and unchanged in 2. The postoperative complications included pneumonia, chylothorax, and pain at the site of skin incision. We were able to minimize these complications in our cases by approaching the affected disc from a posterior transfacet procedure. Most patients with laterally herniated, noncalcified discs can be treated with this approach. Still being debated is whether a fusion should be performed concurrently with the thoracic discectomy. In our series, the patients with disease at 3 levels underwent discectomies via the modified transfacet approach, with concurrent stabilization along with posterior fixation and fusion. Bransford et al. 8 recommended segmental fusion to prevent postoperative spinal instability, especially the long-term progsive instability seen with this approach, to minimize postoperative axial back pain due to the potential increase in motion, and to correct coexisting deformity. 80 J Neurosurg: Spine / Volume 15 / July 2011

6 Transfacet approach for multiple thoracic disc herniations Conclusions Fifteen patients with multilevel TDHs are pented, and their ultant surgical management and outcomes are reported. Penting complaints included back pain, sensory loss, and weakness. Postoperative improvement was seen in all of these categories. All patients were treated with a modified transfacet approach. The limitations to this study are the small series of patients from a single institution, the retrospective review of prospectively collected data, and the absence of formal outcomes instruments. Our experience shows that surgical management of multiple thoracic herniated discs can be achieved via a modified transfacet approach, and with low morbidity and risk to the patient. Disclosure No funding or material support was received for this work. There are no conflicts of intet. Author contributions to the study and manuscript preparation include the following. Conception and design: Arnold. Acquisition of data: Arnold, Johnson. Analysis and interpretation of data: Arnold, Johnson. Drafting the article: Arnold, Anderson. Critically revising the article: Arnold, Anderson. Reviewed final version of the manuscript and approved it for submission: all authors. Administrative/ technical/material support: Anderson. References 1. Abbott KH, Retter RH: Protrusions of thoracic intervertebral disks. Neurology 6:1 10, Alvarez O, Roque CT, Pampati M: Multilevel thoracic disk herniations: CT and MR studies. J Comput Assist Tomogr 12: , Ayhan S, Nelson C, Gok B, Petteys RJ, Wolinsky JP, Witham TF, et al: Transthoracic surgical treatment for centrally located thoracic disc herniations penting with myelopathy: a 5-year institutional experience. J Spinal Disord Tech 23: 79 88, Bhole R, Gilmer RE: Two-level thoracic disc herniation. Clin Orthop Relat Res 190: , Bilsky MH: Transpedicular approach for thoracic disc herniations. 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J Neurosurg 83: , Svien HJ, Karavitis AL: Multiple protrusions of intervertebral disks in the upper thoracic region: report of case. Proc Staff Meet Mayo Clin 29: , Van Landingham JH: Herniation of thoracic intervertebral discs with spinal cord compsion in kyphosis dorsalis juvenilis (Scheuermann s disease); case report. J Neurosurg 11: , Watanabe K, Yabuki S, Konno S, Kikuchi S: Complications of endoscopic spinal surgery: a retrospective study of thoracoscopy and retroperitoneoscopy. J Orthop Sci 12:42 48, 2007 Manuscript submitted September 7, Accepted March 8, Please include this information when citing this paper: published online April 8, 2011; DOI: / SPINE Adds corpondence to: Paul M. Arnold, M.D., 3901 Rainbow Boulevard, Mail Stop 3021, Kansas City, Kansas parnold@kumc.edu. 81