Simultaneously anterior decompression and posterior instrumentation by extrapleural retroperitoneal approach in thoracolumbar lesions

Abstract

Background: Anterior decompression with posterior instrumentation when indicated in thoracolumbar spinal lesions if performed simultaneously in single-stage expedites rehabilitation and recovery. Transthoracic, transdiaphragmatic approach to access the thoracolumbar junction is associated with significant morbidity, as it violates thoracic cavity; requires cutting of diaphragm and a separate approach, for posterior instrumentation. We evaluated the clinical outcome morbidity and feasibility of extrapleural retroperitoneal approach to perform anterior decompression and posterior instrumentation simultaneously by single "T" incision outcome in thoracolumbar spinal trauma and tuberculosis.

Patients and methods: Forty-eight cases of tubercular spine (n = 25) and fracture of the spine (n = 23) were included in the study of which 29 were male and 19 female. The mean age of patients was 29.1 years. All patients underwent single-stage anterior decompression, fusion, and posterior instrumentation (except two old traumatic cases) via extrapleural retroperitoneal approach by single "T" incision. Tuberculosis cases were operated in lateral position as they were stabilized with Hartshill instrumentation. For traumatic spine initially posterior pedicle screw fixation was performed in prone position and then turned to right lateral position for anterior decompression by same incision and approach. They were evaluated for blood loss, duration of surgery, superficial and deep infection of incision site, flap necrosis, correction of the kyphotic deformity, and restoration of anterior and posterior vertebral body height.

Results: In traumatic spine group the mean duration of surgery was 269 minutes (range 215-315 minutes) including the change over time from prone to lateral position. The mean intraoperative blood loss was 918 ml (range 550-1100 ml). The preoperative mean ASIA motor, pin prick and light touch score improved from 63.3 to 74.4, 86 to 94.4 and 86 to 96 at 6 month of follow-up respectively. The mean preoperative loss of the anterior vertebral height improved from 44.7% to 18.4% immediate postoperatively and was 17.5% at final follow-up at 1 year. The means preoperative kyphus angle also improved from 23.3° to 9.3° immediately after surgery, which deteriorated to 11.5° at final follow-up. One patient developed deep wound infection at the operative site as well as flap necrosis, which needed debridement and removal of hardware. Five patients had bed sore in the sacral region, which healed uneventfully. In tubercular spine (n=25) group, mean operating time was approximately 45 minutes less than traumatic group. The mean intraoperative blood loss was 1100 ml (750-2200 ml). The mean preoperative kyphosis was corrected from 55° to 23°. Wound healing occurred uneventful in 23 cases and wound dehiscence occurred in only 2 cases. Nine out of 11 cases with paraplegia showed excellent neural recovery while 2 with panvertebral disease showed partial neural recovery. None of the patients in both groups required intensive unit care.

Conclusions: Simultaneous exposure of both posterior and anterior column of the spine for posterior instrumentation and anterior decompression and fusion in single stage by extra pleural retroperitoneal approach by "T" incision in thoracolumbar spinal lesions is safe, an easy alternative with reduced morbidity as chest and abdominal cavities are not violated, ICU care is not required and diaphragm is not cut.

Keywords: Extra pleural retroperitoneal approach; spinal trauma; thoracolumbar spine; tuberculosis of spine.

Figure 1A

Intraoperative photograph of the exposure showing (a) “T” incision with full thickness fasciocutaneous flap lifted up (b) thoracolumbar fascia incised in the line of incision (c) a plane between iliocostalis and longissimus muscle made (d) skin and muscle flap were reflected and held by stay suture with split in paraspinal muscles seen (e) posterior 6cm of the 11^th and 12^th rib was exposed (f) 12^th rib was subperiosteally removed

Figure 1B

Intraoperative photograph of exposure shows (a) blunt dissection done in front of transverse process creating an anterior flap of muscle of psoas, quadratus lumborum (b) lumbar nerves identified, protected (c) A spatula was placed under reflected psoas muscle exposing anterolateral surface of fractured vertebral body (d) spinal cord decompression done by corpectomy of fractured vertebra and removal of adjacent disc and bed for graft created (e) tri-cortical strut graft from ipsilateral iliac crest, placed between fractured vertebral body and proximal intact vertebral body (f) wound closed in layers

Figure 2

A line diagram of horizontal section of abdomen through thoracolumbar junction showing (a) L1 vertebra with musculature and abdominal wall layers. Thick line denotes the proposed entry from the posterior to anterior underneath quadrates lumborum and psoas major muscle to reach lateral surface to the vertebral body (b) exposure of the lateral surface of body, pedicle and anterior transverse process once psoas major and quadratus lumborum retracted by spatula

Figure 3

(a) Preoperative X-ray of dorsolumbar spine lateral view of 32 years old male with burst fracture (type A) of D12 with preoperative kyphosis of 32°. (b) Immediate postoperative X-ray lateral view after single-stage anterior decompression, bone grating, and pedicle screw fixation via extrapleural retroperitoneal approach, showing correction of kyphosis and well-placed bone graft. (c) Six months postoperative migsaggital reconstructed CT image showing graft incorporation and final kyphosis of 11°

Figure 4

(a) Preoperative X-ray lateral view showing unstable burst fracture (type B) of L1 vertebra. (b) Immediate postoperative X-ray lateral view of the same patient after pedicle screw fixation, anterior decompression, and bone grafting via single-stage extrapleural retroperitoneal approach by “T” incision. (c) Clinical photograph of the “T” incision after 2 week of surgery

Figure 5

(a) Preoperative X-rays lateral view and (b) MRI T2WI of mid sagittal of thoracolumbar spine of a 47-years-old female with pott's spine (panvertebral lesion) showing complete collapse of D12 and kyphosis of 38°. (c) Postoperative X-rays lateral view after singlestage anterior decompression, bone grating, and Hartshill fixation via extrapleural retroperitoneal approach by “T” incision, showing correction of kyphosis and well-placed tricortical bone graft