Original ArticleThe Subcostal Nerve During Lateral Approaches to the Lumbar Spine: An Anatomical Study with Relevance for Injury Avoidance and Postoperative Complications Such as Abdominal Wall Hernia
Introduction
There has been a recent increase in minimally invasive spine surgery. One approach used is the lateral transpsoas approach, refined by Ozgur et al. in 2006.1 Intraoperative monitoring is used when accessing the space between the 12th rib and the iliac crest. Lumbar lateral interbody fusion procedures have gained popularity owing to several advantages, including low blood loss, preservation of the posterior musculature and ligamentous chain, and the ability to perform an extensive discectomy and placement of a large intervertebral graft across the apophyseal ring, leading to indirect decompression.2 As the use of lateral transpsoas approaches continues to increase, it is important for surgeons to be aware of procedural complications, such as postoperative nerve palsies.3
The corridor used to gain access to the retroperitoneal space during the lateral transpsoas approach lies between the 12th rib and the iliac crest, which is supplied primarily by the 11th intercostal and subcostal nerves, with lesser contributions from the 10th intercostal nerve and L1 nerve.4 Minimal access lateral spine exposure involves di2ssection through the abdominal musculature in addition to possible resection of the rib. However, details of the innervation pattern of the abdominal oblique muscles with the initial dissection for this procedure have not been well studied, particularly in relation to lateral abdominal hernias (Figure 1).
Most of the literature on iatrogenic abdominal wall pseudohernias resulting from lateral approaches has been derived from renal and thoracic approaches, where the visible defect may lead to emotional discomfort.5, 6, 7 Therefore, we conducted an anatomical study to study the innervation of the abdominal oblique musculature through a lateral transpsoas approach. We hypothesized that the 12th intercostal nerve provides most of the branches and is the dominant nerve for innervating the lateral abdominal wall between the iliac crest and 12th rib (i.e., the window for lateral approaches to the lumbar spine) in contrast to T11 and L1. Recognition of the most common innervation pattern should guide the surgeon in planning the safest possible surgical corridor and dissection technique.
Section snippets
Methods
Dissection of the lateral abdomen was performed on 10 adult fresh-frozen cadavers (20 sides), 5 males and 5 females, aged 77–92 years at the time of death. On each side, the region between the iliac crest and 12th rib was dissected, with close attention given to the nerves in this region, particularly to their course and muscular supply at the lateral position where transpsoas approaches are performed. The overlying skin, subcutaneous tissues, latissimus dorsi, and associated thoracolumbar
Results
In the lateral position, the subcostal nerve was found to be the predominant nerve in terms of abdominal oblique muscle innervation. It was the largest (average diameter, 6 mm) nerve in this region and had a wider field of distribution with more branches (8 on average) compared with the L1 (4 on average) and 11th intercostal nerves (2 on average) (Figures 2 and 3). L2 contributed only small branches to the lateral abdominal wall musculature on 2 sides. The average diameter of the L1 and L2
Discussion
The intercostal nerves are composed of 4 branches: muscular, collateral, lateral cutaneous, and anterior cutaneous. The collateral branch arises at the angle of the ribs and supplies the intercostal muscles and the parietal pleura as it courses closely with the subcostal vessels.8 The subcostal nerve, which we identified as the dominant nerve in the incision for a lateral transpsoas approach, travels with the subcostal vein and the artery in the inferior aspect of the 12th rib. Whereas the
Conclusion
Knowledge of the specific innervation and nerve dominance pattern for the lateral approach to the spine might help decrease postoperative complications, such as sensory deficits or abdominal wall hernias. The subcostal nerve is the dominant nerve in terms of both size and innervation of the oblique muscles in the lateral position approach.
References (28)
- et al.
Extreme Lateral Interbody Fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion
Spine J
(2006) - et al.
Surgical anatomy of the 10th and 11th intercostal, and subcostal nerves: prevention of damage during lumbotomy
J Urol
(2011) - et al.
Permanent flank bulge is a consequence of flank incision for radical nephrectomy in one half of patients
Urol Oncol
(2004) - et al.
Surgical exposure/anatomy of the lateral lumbar spine and plexus
- et al.
Neurectomy for treatment of intercostal neuralgia
Ann Thorac Surg
(2008) - et al.
Case report: incisional hernia as a complication of extreme lateral interbody fusion
Spine J
(2012) Anatomical variation in the position of the proximal intercostal nerve
Br J Anaesth
(1988)- et al.
Use of a surgical sponge facilitates rib resection in flank incisions
Urology
(1997) - et al.
Delayed abdominal pseudohernia in young patient after lateral lumbar interbody fusion procedure: case report
World Neurosurg
(2016) - et al.
Early outcomes and safety of the minimally invasive, lateral retroperitoneal transpsoas approach for adult degenerative scoliosis
Neurosurg Focus
(2010)
Motor nerve injuries following the minimally invasive lateral transpsoas approach
J Neurosurg Spine
The retroperitoneal incision. An evaluation of postoperative flank ‘bulge’
Arch Surg
Abdominal wall bulging after thoracic surgery, an underdiagnosed wound complication
Hernia
Nerves of the thoracic wall. Clinically Oriented Anatomy
Cited by (19)
Relevant anatomy for lateral access surgery
2022, Seminars in Spine SurgeryCitation Excerpt :Care should be taken not to mistake these nerves for retroperitoneal scar tissue or adhesions during the dissection. The subcostal nerve originates from the T12 root and initially travels within the inferior groove of the twelfth rib and then runs approximately 5 cm below the inferior aspect to the twelfth rib as it crosses the quadratus lumborum to pierce the transversalis fascia.7,8 The reported safe working zone is the midpoint between the twelfth rib and the iliac crest.7
Lateral access techniques for degenerative conditions of the spine
2021, Seminars in Spine SurgeryCitation Excerpt :However, it is thought that with the current emphasis on larger interbody diameters (22 and 26 mm), as well as increased use of titanium interbody cages, the rates of subsidence have been reduced.41 The LLIF approach carries a theoretical risk of injury to the subcostal nerve, which travels along the anterior portion of the quadratus lumborum and perforates and innervates the anterior abdominal wall muscles.42 Such injuries have been reported at a rate of 1.7% in one review of 568 patients undergoing LLIF with resultant transient abdominal wall paresis and abdominal wall hernias; all of these cases resolved without permanent sequelae.43
Minimally invasive extreme lateral lumbar interbody fusion (XLIF) to manage adjacent level disease – A case series and literature review
2021, Interdisciplinary Neurosurgery: Advanced Techniques and Case ManagementCitation Excerpt :The third of these is the iliohypogastric nerve, that is again a mixed sensory and motor nerve, providing sensation from the lateral gluteal region, motor innervation to the external oblique, internal oblique, and transversus abdominus muscles. The fourth of these is the lateral femoral cutaneous nerve that is a sensory nerve providing sensation to the area below the ipsilateral iliac crest and the gluteal area [20,21]. Several additional studies note the consequences of injury to these lateral retroperitoneal neural structures and report that, post the XLIF procedure, new sensory deficits occurred in 0–75% of subjects; new motor deficits occurred in 0.7%–40% of subjects; and anterior thigh/groin pain occurred in 12.5–34% of subjects [19,22,23].
Techniques for the Lateral Thoracolumbar Approach
2019, Surgical Anatomy of the Lateral Transpsoas Approach to the Lumbar SpineComplication rates following stand-alone lateral interbody fusion: a single institution series after 10 years of experience
2023, European Journal of Orthopaedic Surgery and Traumatology
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.