Early experience treating thoracic disc herniations using a modified transfacet pedicle-sparing decompression and fusion
Authors: Bransford Richard , Zhang Fangyi , Bellabarba Carlo , Konodi Mark , Chapman Jens R. 
Published: February 2011

Object
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.

Methods
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.

Results
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.

Conclusions
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.