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0Clinical study of a new approach to thoracolumbar surgery
LIU Gang M№1*, ZHAO Jian-ning MMt and Akira Dezawa
Objective: The conventional approaches for treatment of thoracolumbar diseases require extensive surgical exposure, often leading to postoperative pain and morbidity. Thoracoscopic-assisted surgery in these regions usually requires an extended recovery period due to the placement of drainage. We developed an innovative retro-peritoneal-extrapleural approach to thoracolumbar involvement by an extra-diaphragmatic technique using dedicated instruments. Neither incision nor reconstruction of the diaphragm was necessary. Exposure to the lateral part of the thoracolumbar vertebrae could be achieved without crus resection. This study is aimed to evaluate the clinical outcomes of this new surgical procedure.
Methods: A total of 9 cases (5 cases of thoracolumbar fracture-dislocation, 1 each of spinal infection, tumor, thoracolumbar scoliosis and ossification of posterior longitudinal ligament) were subjected to the study. The average age of the patients was 52.3 years. The results were com-
pared with the control group consisting of thoracoscopic surgery subgroup (5 patients, mean age 52.1 years) and conventional surgery subgroup (12 patients, mean age 61.3 years).
Results: Compared with the control group, the average period of bed confinement and mean intra- and postoperative blood loss decreased significantly. Pulmonary complications were avoided in all cases. The surgical time was shortened, postoperative pain was reduced, and early postoperative ambulation became possible.
Conclusion: The diaphragm-preserving retroperito-neal-extrapleural approach that we developed is a valid minimally invasive alternative for the treatment of thora-columbar diseases.
Key words: Thoracic vertebrae; Lumbar vertebrae; Fractures, bone; Surgical procedures, minimally invasive
Chin J Traumatol 2008; 11(3):148-151
The retroperitoneal-extrapleural approach is a sur gical procedure that gets access to the spine extra-diaphragmatically. This allows a direct, anterolateral access to the lesion localized at the anterior vertebrae that compresses the spinal cord. It is a modified version of the conventional technique that involves a partial incision of the diaphragm. With the endoscopic retroperitoneal-extrapleural approach, T12-L3 segment vertebrae can be accessed with no incision of the diaphragm. We also developed the instrument dedicated to this application. The indications for this approach include: vertebrae fracture-dislocation, bone caries, spinal infection, primary and metastatic thoracic vertebrae tumor, correction of thoracic scoliosis,
Department of Orthopaedic Surgery, Nanjing General Hospital of Nanjing Military Command, Nanjing 210001, China (Liu G and Zhao JN)
Department of Orthopaedic Surgery, Teikyo University Mizonokuchi Hospital, Kanagawa 213-8507, Japan ( Dezawa A)
Corresponding author: Tel:86-13770658178, E-mail: liug2002xian@yahoo.com
herniated discs and ossification of posterior longitudinal ligament (OPLL).
METHODS
A total of 9 cases (5 cases of thoracolumbar frac-ture-dislocation,1 each of spinal infection, tumor, thoracolumbar scoliosis and OPLL) were included in the study. The average age of the patients was 52.3 years. The clinical results were compared with the control group consisting of thoracoscopic surgery subgroup (5 patients, mean age 52.1 years) and conventional surgery subgroup (12 patients, mean age 61.3 years).
The intraoperative blood loss, the duration of the operation, the postoperative period of lying in bed and the period of hospital stay were evaluated compared to the control groups. An unpaired t test was used to evaluate the differences in the three groups. All data were analyzed with the SPSS software 15.0 and P<0.05 was considered as statistically significant.
Peripheral (adjacent) diaphragm anatomy
The rib bed was composed of three layers, the periosteum and endothoracic fascia, and the parietal pleura were identified. Normally, the incision and dissection of the parietal pleura were made after accessing the cavity between the endothoracic fascia and the parietal pleura. The pleura occasionally extended to the tip of the 11th rib, but usually it ran slightly more proximal to the tip of the 11th rib. (Fig.1)
Surgical technique
A pillow was put under the patient's trunk or the operating table was adjusted to the jackknife position. A 5-7 cm incision was made over the 11th rib. An anterior thoracicolumbar retractor was used to make good exposure (Fig.2).If the 11th rib did not interfere with manipulation, it was also possible to excise the 12th rib to ensure a good access to the vertebral body extraperiosteally. An incision could then be made in the diaphragm which adhered to the periosteum of the cephalad part of the 11th rib. However, in most cases, the rib insertion part of the diaphragm was excised subperiosteally in the direction toward the 12th rib. The periosteum of the rib was separated on the rib bed along the entire length up to the rib base and the 11th rib was excised completely at the costotransverse junction. Hence the side of a vertebral body was exposed. Cephalad dissection was carefully performed outside the parietal pleura. As the parietal pleura, close to the vertebral body, was thick and hardly tore. Unlike the ventral pleura, it could be separated in the proximity of the vertebral body, usually from back to front (Fig.3). The intercostal nerve served as a landmark for the decompression of the spinal canal. The posterior part of the diaphragm was the lumbocostal arch, which adhered to a transverse process of the first lumbar vertebra. Different from the conventional method by which the lumbocostal arch was excised, this method involved the detachment of the ligament from the transverse process. The anterior part of lumbocostal arch ran toward the front of the 1st and 2nd lumbar vertebral bodies, forming the corresponding crus. The ligament covered over the psoas major muscle.
There was no need to place drainage in the retroperitoneal-extrapleural cavity. The drainage was placed only to prevent haematoma formation in the surgical wound and it could be removed 1 -2 days postoperatively. Using this approach, even the L3 vertebral body could
be well exposed without the need for incising or suturing the diaphragm. However, due to the small size of the incision, which restricted the view, special endo-scopic-assisted instrument was required. Although it was often difficult to confirm the validity of a decompression procedure, endoscopic visualization ensured the safety.
As for the cephalad part of the 10th rib, the rib head lies between intervertebral discs. Even though the head of the 11th rib remained partially unexcised, the manipulation of the intervertebral disc was still possible because the 11th and 12th ribs are floating ribs that are attached to the vertebrae only.
The following points should be checked preoperatively: 1) the length of the 12th rib; 2) the level of the subordinate portion of the pleura at maximum inspiration; 3) the level of the inferior edge of the 10th rib intersecting with the vertebral body on the posterior axillary line when the patient is in extension position; and 4) existence of radiculopathy at the thoracolumbar conjunction.
When the inferior edge of the 10th rib was revealed to hang over the first lumbar vertebra, the fixation of the first lumbar vertebra often became difficult. For instance, in the case of the second lumbar vertebral comminuted fracture, the intervertebral height was obtained using retroperitoneal endoscopy to perform decompression of spinal canal and vertebral fusion (Figs. 4, 5).
RESULTS
Clinical parameters and results of the control groups were as follows (thoracoscopic approach group/conventional approach group):blood loss 726/832 ml;op-eration time 284/308 min;drainage placing period 3.5/ 4.2 days; hospital stay 33.3/34.4 days; gait initiation 3.2/5.2 days; JOA improvement 86.6%/89.6%.
While, as a rule, the placement of a drainage in the thoracic cavity was not necessary. A drainage was inserted at the wound for a short period (1.5 days on average) only as prophylaxis of haematoma formation. Intraoperative blood loss was 423 ml with significant difference of the two other groups(P<0.05, Fig.6).Op-eration time was on average 286 minutes. The hospital stay was 23.1 days (14-41days) with gait initiation in
2.1 days postoperatively (P<0.05 vs the conventional approach group, Fig. 7).The JOA improvement rate was 85.7%.The bone was healed in all cases.
Fig.1. Peripheral (adjacent) diaphragm anatomy.
Fig. 2. Endoscopic-assisted anterior thoracicolumbar retractor.
Fig. 3. The extradiaphragmatic approach, with the 11th rib removed.
Preoperation Postoperation
Fig. 4. The pre- and post-operative X-ray of the second lumbar vertebral comminuted fracture performed by retroperitoneal-extrapleural approach.
Fig. 5. An intraoperative photograph of the retroperitoneal-extrapleural approach.
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Fig. 6. The mean intraoperative blood loss of the three groups. REA shows significant difference with the two other approaches ( P<0.05). TA, CA, REA stand for thoracoscopic approach, conventional approach and retroperitoneal-extrapleural approach respectively.
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Fig. 7. The mean postoperative lying in bed time of the three groups. P<0.05 vs the conventional approach group.
DISCUSSION
In the conventional approach, the 11th rib is usually excised extrapleurally from its tip to obtain an access to the peritoneal cavity caudally. The 11th rib bed is incised, followed by the resection between the parietal pleura and the rib bed (periosteum) to approach the vertebral body. This method requires the separation of the thin and easily torn pleura in the vicinity of the diaphragm adhesion layer. As the vertebral body is
accessed by a circular incision of the diaphragm, it is
necessary to suture the diaphragm after the procedure. The operation technique is complex and highly invasive. Though the thoracoscopic transdiaphragmatic approach
proposed by Beisse et al34 requires only a small incision, it is still necessary to place drainage in the thoracic cavity.
In comparison with the conventional approaches, the retroperitoneal-extrapleural approach of this method is advantageous because: 1) Incision is required only in the part of the diaphragm crura that adheres to the vertebral transverse process. 2) Suture of the diaphragm is not needed. 3) Insertion of drainage in the thoracic cavity is not necessary. 4) Complications of pyothorax can be avoided in cases of vertebral inflammation such as spine tuberculosis. 5) Postoperative pain can be alleviated, enabling an early onset of gait training. 6) The dissection of up to two segments of intervertebral disc tissue allows preservation of the intercostal nerve, thus preventing lasting postoperative symptoms related to the intercostal nerve. 7) Unlike the thoracoscopic surgery, a special training for eye-hand coordination is not necessary and the entire process of the surgery can directly be observed with bare eyes. 8) The challenge level of training can minutely increase from the approach by direct viewing to the thoracoscopic surgery. 9) As the 11th and 12th ribs are the floating ribs, the vertebrae can be accessed without injury of the rib cage. 10) The dissection can be extended cranially or/and caudally, if required. 11) If the manipulation is performed up to the 11th vertebrae, bilateral lung ventilation is possible rather than single lung ventilation.
The present study has also showed that retroperi-toneal-extrapleural approach could dramatically decrease the intraoperative blood loss compared with the other two approaches and the gait initiation in 2.1 d ays postoperatively, which was significantly decreased compared with the conventional approach group. At the same time, JOA score has no difference in the three groups. It seems to demonstrate that the retroperitoneal-extrapleural approach is a fine minimally invasive alternative for the lesion in such regions.
The downsides of this approach include: 1) The implants should be compatible with special instruments that are used to manipulate the vertebrae laterally within the limited space. 2) Dedicated instruments are required. 3) It is difficult to feel the boundary of internal organs. 4) As the decompression of vertebrae is performed laterally, the methods of use of chisels and
speed burrs are different from conventional methods. Appropriate training may be necessary.56
In conclusion, this novel retroperitoneal-extrapleural approach, which does not need an incision and reconstruction of the diaphragm, can not only alleviate the postoperative pain, but also eliminate the use of drainage in the thoracic cavity, enabling the patient's early rehabilitation.
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(Received April 4, 2007) Edited by SONG Shuang-ming
