Are Dural Tears in Minimal Invasive Spine Surgery of the Lumbar Spine More Forgiving than in Open Spine Surgery?

Presented at SMISS Global Forum 2014
By Arvind Kulkarni MS(ORTH) Dip(ORTH) FCPS Dip(SICOT)

Disclosures: Arvind Kulkarni MS(ORTH) Dip(ORTH) FCPS Dip(SICOT) None

Introduction:
There is a paucity of literature comparing the management and outcomes of CSF leaks in OSS and MISS. Aims/Objectives: To compare the outcomes of CSF leaks in open spine surgery (OSS) and minimal invasive spine surgery (MISS).

Methods:
All OSS and MISS cases during the study period from April2007-May 2012 with an accidental dural-tear were retrospectively analysed. MISS surgeries included procedures done using tubular retractors. The parameters, 1) delay in mobilization and 2) excess duration of hospital stay were analysed using IBM® SPSS® Statistics version 20.

Results:
The total number of spine surgeries performed in the study period was 1023. Dural tears occurred in 23/669 cases of OSS (3.43%) and in 22/354 (6.21%) cases of MISS.In OSS- 20 tears were recognised intra-operatively and repaired, followed by bed-rest for 48-72 hours and then mobilised. Two cases with persistent CSF-leak required re-exploration and repair. In 3 cases with post-operative CSF collection, insertion of a lumbar-drain helped in resolution of symptoms with 2 cases needing re-admission for 5 days. In MISS-group, there were 20 minor-tears and 2 extensive tears. In the first 7minor-tears, fibrin-glue was sprayed over the tear and the last 13tears were left alone. One patient with a large tear was treated with approximation of the edges and the other needed an open repair. All patients were mobilised after 24 hours, except for the patient with the open repair (48 hours). The mean delay in mobilization was 78.26 hours (OSS) and 26.18 hours (MISS), and the excess stay was 2.35 days (OSS) and 1.5 days compared to cases without DTs in each group. The difference in the two groups was statistically significant (p < 0.005).

Conclusions:
A large dead-space encourages collection of CSF requiring adequate repair and/or insertion of a lumbar drain in OSS. While extensive tears may need conversion to open repair in MISS, a large majority of these tears are small and can be left alone without any consequences. The absence of a ‘dead-space’ after withdrawing the tubular retractor discourages CSF collection. The management of an incidental durotomy may increase the overall hospital costs in OSS cases as compared to cases dealt with MISS. MISS, being a soft-tissue and bone-sparing surgery prevents spread of CSF-leak outside the spinal-canal.