Fernando Alonso1, Rachel Graham2, Tarush Rustagi3, Doniel Drazin4, Marios Loukas5, Rod J Oskouian4, Jens R Chapman4, R Shane Tubbs6. 1. Swedish Neuroscience Institute, Seattle, Washington, USA; Seattle Science Foundation, Seattle, Washington, USA. Electronic address: Fea4@case.edu. 2. Seattle Science Foundation, Seattle, Washington, USA. 3. Swedish Neuroscience Institute, Seattle, Washington, USA; Department of Spine Surgery, Indian Spinal Injuries Centre, New Delhi, India. 4. Swedish Neuroscience Institute, Seattle, Washington, USA. 5. Department of Anatomical Sciences, St. George's University, St George, Grenada. 6. Seattle Science Foundation, Seattle, Washington, USA; Department of Anatomical Sciences, St. George's University, St George, Grenada.
Abstract
BACKGROUND: Lateral approaches to the spine are increasing in popularity. However, details of the innervation pattern of the abdominal oblique muscles with the initial dissection have not been well studied. METHODS: Ten adult fresh-frozen cadavers (20 sides) were placed in the lateral position. On each side, the region in which transpsoas approaches are performed, between the iliac crest and the 12th rib, was dissected. The nerves, their course, and their muscular supply were studied. RESULTS: The subcostal nerve is the predominant nerve supply for the anterolateral abdominal muscle innervation. It is larger and has a wider field of distribution and more branches (8 on average) compared with the L1 (4 on average) and 11th intercostal nerves (2 on average 2). The proximal 6-10 cm of each nerve has few if any branches. The subcostal nerve is often (75%) located up to 5 cm inferior to the 12th rib in its initial course. The area of least concentration ("safe zone") is located at an approximate midpoint between the lower edge of the 12th rib and the superior-most aspect of the iliac crest. A previously undescribed branch of the subcostal nerve was found traveling posterior to the quadratus lumborum and joining the remaining subcostal nerve in an anastomosis at or near the lateral position. CONCLUSIONS: Knowledge of the innervation and nerve dominance patterns might help decrease postoperative complications such as sensory deficits or abdominal wall hernias. The subcostal nerve is the dominant nerve in both size and innervation of the oblique muscles in the lateral position, transpsoas approach.
BACKGROUND: Lateral approaches to the spine are increasing in popularity. However, details of the innervation pattern of the abdominal oblique muscles with the initial dissection have not been well studied. METHODS: Ten adult fresh-frozen cadavers (20 sides) were placed in the lateral position. On each side, the region in which transpsoas approaches are performed, between the iliac crest and the 12th rib, was dissected. The nerves, their course, and their muscular supply were studied. RESULTS: The subcostal nerve is the predominant nerve supply for the anterolateral abdominal muscle innervation. It is larger and has a wider field of distribution and more branches (8 on average) compared with the L1 (4 on average) and 11th intercostal nerves (2 on average 2). The proximal 6-10 cm of each nerve has few if any branches. The subcostal nerve is often (75%) located up to 5 cm inferior to the 12th rib in its initial course. The area of least concentration ("safe zone") is located at an approximate midpoint between the lower edge of the 12th rib and the superior-most aspect of the iliac crest. A previously undescribed branch of the subcostal nerve was found traveling posterior to the quadratus lumborum and joining the remaining subcostal nerve in an anastomosis at or near the lateral position. CONCLUSIONS: Knowledge of the innervation and nerve dominance patterns might help decrease postoperative complications such as sensory deficits or abdominal wall hernias. The subcostal nerve is the dominant nerve in both size and innervation of the oblique muscles in the lateral position, transpsoas approach.
Authors: Periklis Godolias; Zachary L Tataryn; Sven Frieler; Ravi Nunna; Kaarina Charlot; Angela Tran; Jonathan Plümer; Charlotte Cibura; Hamzah Al-Awadi; Zeyad Daher; Marcel Dudda; Thomas A Schildhauer; Jens Chapman; Rod Oskouian Journal: Eur J Orthop Surg Traumatol Date: 2022-10-14