Treating thoracic-disc herniations: Do we always have to go anteriorly?

Abstract

Study design: Retrospective cohort study.

Objective: To determine if there is a difference in outcome and complications in surgically managed patients with thoracic-disc herniations (TDH) undergoing a modified transfacet pedicle-sparing decompression and fusion (posteriorly) compared to those undergoing anterior transthoracic discectomies (anteriorly).

Methods: Thirty-five consecutive operatively managed TDH underwent operative management between March 2003 and November 2009. Outcomes and complications were reviewed from patient records and x-rays assessing differences between those treated posteriorly and those treated anteriorly.

Results: Twenty-four patients underwent posterior management for 35 TDH and ten patients underwent anterior management for twelve TDH. Mean age was 50 years in both groups. Body mass index (BMI) averaged 28.8 in the anterior group and 32.0 in the posterior group. Follow-up averaged 38 weeks with four patients lost to follow-up (all posterior). Major complications secondary to surgery occurred in three patients (30%) in the anterior group (pulmonary embolus, pneumonia, and wrong level surgery) and in seven patients (35%) in the posterior group (seroma, misplaced instrumentation requiring revision, recurrence requiring an additional operation, and four infections). No neurological complications occurred and all patients noted improvement from baseline. Average length of stay was 7.3 days in the anterior group and 4.2 days in the posterior group (P < .003). Final pain as assessed by visual analog scale (VAS) improved from 6.7 to 4.3 in the anterior group and 6.9 to 2.3 in the posterior group (P = .05).

Conclusions: Complication rates are similar between groups and are approach related. Posteriorly managed patients had greater improvement in pain and shorter length of stay.

References

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Editorial staff perspectives

This is a CoE III treatment study.

Bransford et al compare approaches to treating thoracic disc herniation, which is rare relative to cervical and lumbar herniations. This study provides an example of the challenges related to studying rare conditions, the primary and most obvious being small numbers of patients available for study and the long period of time required to accumulate enough cases to study. These factors make prospective studies (randomized controlled trials or traditional prospective cohort studies) more difficult to design and implement, and use of retrospective cohort studies or other study designs more appealing and feasible.

Timing:

It may take a long time for a single surgical center to accrue a sufficient number of cases; however, changes in technology, treatment options and perspectives continue over that time period and may be rapid. Endoscopic transthoracic discectomy provides an example: After initial enthusiasm for it as a less invasive, more benign alternative to open transthoracic discectomy, lack of comparative studies or evidence of its effectiveness and safety in real life applications resulted in a rapid decline in its popularity. Thus, it may have been of questionable value to have this as an intervention arm in a lengthy or time-sensitive study.

Study design:

With rare conditions such as TDH, or other instances where randomized controlled trials are not feasible or ethical, outcomes from methodologically rigorous nonrandomized cohort studies may provide the best approximation of what might be observed in RCTs. Such studies can take surgeon training and preferences and patient preferences into account. These studies must, however, have carefully defined exclusion criteria, and document and consider prognostic factors. In addition, the patient and surgeon preferences must be well understood [King]. Regardless of the study design chosen, attention must be given to methods of reducing bias and accounting for potentially confounding factors.

While single studies like the one by Bransford will not change the current standard of care (anterior transthoracic surgery) for symptomatic TDH causing cord compression, it provides a foundation for further study. A multi-center, collaborative study may provide an opportunity to aggregate a larger number of patients to further evaluate treatment options for TDH.

Reference

King M, Nazareth I, Lampe F, et al (2005) Impact of participant and physician intervention preferences on randomized trials: a systematic review. Jama; 293: 1089 – 1099.