Calcified giant thoracic disc herniations: considerations and treatment strategies

The authors evaluated the clinical and surgical outcomes obtained in patients with giant herniated thoracic discs (HTDs), defined as occupying more than 40% of the spinal canal. Surgery-related considerations and functional outcomes in patients with small- and medium-sized HTDs were compared. The authors reviewed 140 cases of surgically treated HTDs, 20 (14%) of which were giant. Before and after surgery, all patients underwent computerized tomography myelography, magnetic resonance imaging, or both. Functional outcomes were assessed using the Frankel grading system preoperatively, immediately after surgery, and at long-term follow-up examination. The results observed in patients with giant HTDs were compared with those with small- and medium-sized HTDs. The mean overall follow-up period was 2.6 years. Sixty-six patients (47%) presented with myelopathy, including 19 (95%) with a giant HTD. Of the latter, 16 (80%) underwent anterior, eight thoracoscopic, and eight open thoracotomy approaches. Four patients (20%) with laterally oriented giant HTDs within the spinal canal underwent surgery via a posterolateral approach. Based on analysis of long-term follow-up data, 53% of patients with giant HTDs improved neurologically by one Frankel grade. Progression of myelopathy was arrested in 42%, and in 5% the Frankel grade worsened by one. In patients with small- and medium-sized HTDs, the Frankel grade improved by one in 77%, stabilized in 23%, and worsened in 0%. Patients with giant HTDs who underwent thoracoscopic surgery had worse short- and long-term functional outcomes than those in whom open thoracotomy was performed. Patients with giant HTDs presented more frequently with myelopathy and experienced worse functional outcomes than those with smaller HTDs. Based on their experience, the authors recommend open thoracotomy rather than thoracoscopy for the treatment of midline giant HTDs.

Symptomatic herniated thoracic discs remain a surgical challenge and historically have been associated with significant complications. While neurological outcomes have improved with the abandonment of decompressive laminectomy, the attempt to minimize surgical complications and associated morbidities continues through less invasive approaches. Many of these techniques, such as thoracoscopy, have not been widely adopted due to technical difficulties. The current study was performed to examine the safety and early results of a minimally invasive lateral approach for symptomatic thoracic herniated intervertebral discs. Sixty patients from 5 institutions were treated using a mini-open lateral approach for 75 symptomatic thoracic herniated discs with or without calcification. The mean age was 57.9 years (range 23-80 years), and 53.3% of the patients were male. Treatment levels ranged from T4-5 to T11-12, with 1-3 levels being treated (mean 1.3 levels). The most common levels treated were T11-12 (14 cases [18.7%]), T7-8 (12 cases [16%]), and T8-9 (12 cases [16%]). Symptoms included myelopathy in 70% of cases, radiculopathy in 51.7%, axial back pain in 76.7%, and bladder and/or bowel dysfunction in 26.7%. Instrumentation included an interbody spacer in all but 6 cases (10%). Supplemental internal fixation included anterolateral plating in 33.3% of cases and pedicle screws in 10%; there was no supplemental internal fixation in 56.7% of cases. Follow-up ranged from 0.5 to 24 months (mean 11.0 months). The median operating time, estimated blood loss, and length of stay were 182 minutes, 290 ml, and 5.0 days, respectively. Four major complications occurred (6.7%): pneumonia in 1 patient (1.7%); extrapleural free air in 1 patient (1.7%), treated with chest tube placement; new lower-extremity weakness in 1 patient (1.7%); and wound infection in posterior instrumentation in 1 patient (1.7%). Reoperations occurred in 3 cases (5%): one for posterior reexploration, one for infection in posterior instrumentation, and one for removal of symptomatic residual disc material. Back pain, measured using the visual analog scale, improved 60% from the preoperative score to the last follow-up, that is, from 7.8 to 3.1. Excellent or good overall outcomes were achieved in 80% of the patients, a fair or unchanged outcome resulted in 15%, and a poor outcome occurred in 5%. Moreover, myelopathy, radiculopathy, axial back pain, and bladder and/or bowel dysfunction improved in 83.3%, 87.0%, 91.1%, and 87.5% of cases, respectively. The authors' early experience with a large multicenter series suggested that the minimally invasive lateral approach is a safe, reproducible, and efficacious procedure for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional surgical techniques and without the use of endoscopes. Symptom resolution was achieved at similar rates using this approach as compared with the most efficacious techniques in the literature, and with fewer complications in most circumstances.

Symptomatic thoracic disc herniations (TDHs) are relatively uncommon and are typically treated with an anterior approach. Various posterior surgical approaches have been developed to treat TDH, but the gold standard remains transthoracic decompression. Certain patients have comorbidities and herniation aspects that are not optimally treated with an anterior approach. A transfacet pedicle-sparing approach was first described in 1995, but outcomes and complications have not been well described. The objective of this study was to assess outcomes and complications in a consecutive series of patients with TDH undergoing posterior transfacet decompression and discectomy with posterior instrumentation and fusion. Eighteen consecutive patients undergoing operative management of TDH were identified from a tertiary care referral database. All patients underwent a transfacet pedicle-sparing decompression and segmental instrumentation with interbody fusion. Outcomes and complications were retrospectively assessed in this patient series. Clinical records were scrutinized to assess levels and types of disc herniation; blood loss; pre- and postoperative motor scores, Nurick grades, and visual analog pain scale scores; and complications such as wrong-level surgery, infection, seroma, and neurological changes. Pre- and postoperative imaging studies were reviewed to assess levels and types of herniation, alignment, and accuracy of instrumentation. Of the 18 patients, 9 had TDHs at multiple levels. The patients presented with symptoms including myelopathy, axial back pain, urinary symptoms, and radiculopathy and radiological evidence of 29 compressive TDHs ranging from T1-2 to T12-L1. Discs were classified as central (10) or paracentral (19). All discs were successfully removed with no incidence of wrong-level surgery or CSF leak. The mean estimated blood loss was 870 ml with no dural tears. Nurick grades improved on average from 2.5 to 1.9. All patients reported improvement in symptoms compared with preoperative status. The mean visual analog scale score improved from 59 to 21. Sixteen of the 18 patients spent an average of 4.2 days in the hospital; the 2 other patients spent 58 and 69 days. The average duration of follow-up was 12.2 months in 14 patients; 4 patients were lost to follow-up. Twelve patients had no complications. Five patients developed postoperative wound infections or seromas requiring additional operative debridement. One patient had a misplaced screw and suboptimally positioned interbody graft requiring revision. One transient neurological deterioration (American Spinal Injury Association [ASIA] D to ASIA B) occurred postoperatively associated with an inferior segment fracture 20 days after surgery. This necessitated extending the fusion caudally; the patient subsequently experienced a full return to better-than-baseline neurological status. A modified transfacetal pedicle-sparing approach combined with short segmental fusion offers a safe means of achieving concurrent decompression and segmental stabilization and is an option for certain subtypes of TDH. Although 6 patients required additional surgery for postoperative complications, all patients experienced improvement relative to their preoperative status.