Surg Radiol Anat (2009) 31:251–257 DOI 10.1007/s00276-008-0435-1 123 ORIGINAL ARTICLE Surgical anatomy of the presacral area Mustafa Güvençer · Sedat Dalbayrak · Hamid TayeW · Süleyman Tetik · Mesut YÂlmaz · Ufuk Erginoflu · Özdil Baksan · Salih Güran · Sait Naderi Received: 17 June 2008 / Accepted: 17 October 2008 / Published online: 8 November 2008  Springer-Verlag 2008 Abstract Objective L5–S1 instabilities can be Wxated using mini- mally invasive presacral approach. The close relationship between the sacrum and neurovascular as well as intestinal structures may complicate the procedure during this approach. This requires knowledge regarding the normal anatomy of the presacral area to avoid the iatrogenic inju- ries. The aim of this study was to measure the distance between the sacrum and the structures anterior to it. Materials and methods The measurements were per- formed on ten cadavers Wxed with formaldehyde and ten MR imaging studies on individuals without any pathology in the presacral area. The distances between the sacrum and the presacral structures (i.e., middle and lateral sacral arter- ies, sympathetic trunks, internal iliac arteries and veins, and colon/rectum) were measured. Results Cadaver study showed that the middle sacral artery was located on the right side in 55.0%, on the left side in 31.7%, and on the midline in the 13.3% of cases. The distance between the sacral midline and middle sacral artery was found to be 8.0 § 5.4, 9.0 § 4.9, 8.7 § 6.0, 8.6 § 6.4, and 4.7 § 5.0 mm at the levels of S1–2, S2–3, S3–4, S4–5, and S5–coccyx, respectively. The distance between the sacral midline and the sympathetic trunk ranged between 22.4 § 5.8 and 9.5 § 3.2 mm in diVerent levels between S1 and coccygeal level. The study also showed that the distance between the posterior wall of the intestine (colon/rectum) and the ventral surface of the sacrum can be as close as 11.44 § 7.69 mm on MR images. Conclusion This study showed that there was close dis- tance between the sacral midline and the structures anterior to it. The close relationships, as well as the potential for anatomical variations, require the use of sacral and presa- cral imaging before presacral approach. Keywords Middle sacral artery · Presacral anatomy · Presacral approach · Sympathetic trunk Introduction L5–S1 intervertebral disc level has been the target of fusion in many clinical situations, including L5–S1 instability, lumbar degenerative scoliosis, and L5–S1 pseudoarthrosis [1, 6, 16, 25]. This level can be Wxated using classical ante- rior, posterior, and lateral approaches. Some rare surgical procedures, such as total L5 spondylectomy with recon- struction of the lumbosacral junction by ventral approach, need evaluation of structures in presacral area to mobilize vascular structures during surgical stage [12]. Recently, a novel minimally invasive presacral approach has been pro- posed to Wxate L5–S1 level axially [6, 16, 26]. This approach requires a small incision lateral to the sacrococ- cygeal junction, blunt dissection anterior to the sacrum, drilling at the level of S1–2, and Wxation of the L5–S1 level. Although there is no need for neural and muscular M. Güvençer (&) · H. TayeW · S. Tetik Department of Anatomy, School of Medicine, Dokuz Eylül University, 35340 Balçova, Izmir, Turkey e-mail: mustafa.guvencer@deu.edu.tr S. Dalbayrak · M. YÂlmaz · U. Erginoflu The First Department of Neurosurgery, Dr Lütfü KÂrdar Research Hospital, Istanbul, Turkey Ö. Baksan · S. Güran Sonomed Radiodiagnostic Center, Istanbul, Turkey S. Naderi Department of Neurosurgery, Ümraniye Education and Research Hospital, Istanbul, Turkey