Keywords
decompression, surgical - laminectomy - randomized controlled trial - thoracic vertebrae
- ultrasonics
Introduction
Thoracolumbar spine degenerative disease is a major cause of disability worldwide.
Spondylolisthesis, disc degeneration, and spinal stenosis are examples of such disorders.
Thoracolumbar degenerative spine disease can lead to a reduction in the quality of
life with a variety of clinical symptoms, including radiculopathy, weakness, and low
back pain of varying levels of severity.[1] Improving surgical safety and preventing complications in spinal surgery is important
given the increasing frequency of spinal surgery and the aging of patients having
these operations in recent decades. Decompressive laminectomy, which has greater risks
of nerve or dura injury or uncontrollable bleeding and takes a lot of time to accomplish,
is one of the most important procedures in degenerative spinal surgery.[2]
[3]
[4]
[5] Therefore, a major concern in spinal decompression is how to minimize intraoperative
bleeding, reduce the operating time, and improve safety.
The Kerrison rongeurs and high-speed burrs are traditional instruments that have been
used for a long time in spinal decompression. It has the advantages of being available
in a variety of sizes, having great cutting characteristics, and being inexpensive.
However, when using high-speed burrs, the proximity of spinning parts to structures
such as nerves, vessels, and dura maters along with the associated heat damage to
the surrounding tissues can limit their use or result in iatrogenic injury.[6]
[7]
Ultrasonic devices, which were initially designed for dentistry, first emerged in
1952.[8] By the 1970s, technology had advanced to the point that meningioma and vestibular
schwannoma could be effectively debulked and removed.[9]
[10] Only bone is cut while using the ultrasonic bone scalpel (UBS) since its blade is
generated at a frequency of 22.5 kHz. It provides the advantages of accurate bone
cutting, minimizing damage to surrounding tissue, and reducing blood loss.[11]
Several studies have found the ultrasonic bone scalpel to be a safe method of cutting
bone,[6]
[12]
[13] but none of these studies has investigated the outcomes of its utilization in thoracolumbar
spinal surgery. The purpose of the present study is to compare intraoperative blood
loss, operating time, laminectomy time, hospital length of stay, and complications
in thoracolumbar spinal decompression using UBSs with conventional procedures.
Methods
Study Design
This is a single-center, prospective randomized controlled, non-inferiority trial.
The study was approved by the Hatyai Hospital's Institutional Review Board (IRB No.61/2564)
and registered by the Thai Clinical Trials Registry (TCTR20200106003) – the approved
randomized controlled trial was conducted at the Department of Orthopedics, Hatyai
Hospital, Thailand. It included 31 patients that underwent thoracolumbar spinal decompressive
laminectomy and posterior instrumented fusion performed by the first author (Rittipoldech
C.). He has experience of performing 20 thoracolumbar laminectomy procedures with
a UBS. The inclusion criteria were a degenerative thoracolumbar spinal disease with
a plan for decompressive laminectomy and pedicular screw fusion with a surgical level
of 1 to 5 levels and an age range of 40 to 90 years old. The exclusion criteria were
a history of spinal surgery, coagulopathy problems, end-stage renal disease, spinal
tumor, spinal infection, congenital spinal stenosis, inflammatory pathology disease,
or allergy to tranexamic acid.
Forty-two patients who underwent decompressive laminectomy and pedicular screw fusion
with a surgical level of 1 to 5 levels between February 1, 2020, and June 30, 2022
in a single institution were evaluated for eligibility, and 11 were excluded due to
a history of spinal surgery (n = 3), spinal tumor (n = 3), or spinal infection (n = 5). Blinded block randomization at the inclusion of the 31 patients allocated them
to 1 of 2 groups: the UBS group (n = 15), in which a thoracolumbar spinal decompression was performed with the UBSs,
and the conventional group (n = 16), in which the decompression was performed with the Kerrison rongeurs and high-speed
burrs ([Fig. 1]).
Fig. 1 Flowchart of enrollment.
Patients Evaluation and Imaging Feature
Patients in both the UBS and conventional groups experienced typical thoracolumbar
spinal stenosis symptoms, including numbness and weakness in the lower limbs. Plain
X-rays and magnetic resonance imaging (MRI) of the thoracolumbar and lumbosacral spine
were performed on all patients. Magnetic resonance imaging revealed that both groups
had a degenerative spinal disease, ligamentum flavum hypertrophy, or neural compression
associated with symptoms.
Surgical Technique
In all patients, the patient was placed in the prone position after general anesthesia
and antibiotic was administered. Fluoroscopy was used to assess the confirm levels.
A posterior midline incision was made to expose the lamina and the transverse processes
of the affected segment. Rongeurs were used to remove the dorsal spinous process,
the supraspinous ligament, and the interspinous ligament.
For the UBS group, the lamina was cut longitudinally along the midline of the bilateral
facet joints using an UBS (BoneScalpel, Misonix, NY, USA) until the full thickness
of the bone structure, including the lamina and ossified ligament, was uncovered.
It is critical to keep the tip of the UBS moving and not to hold it in one place for
too long. It is also essential to push it farther. When the bone cut is completed,
a give-way sensation is felt, and this is the finishing point. Afterwards, the cephalad
and caudal lamina were separated. The lamina was grasped at one end and gently lifted
with towel clamp forceps as the ossified ligaments and lamina began to loosen. Simultaneously,
the adhesions were released with a nerve stripper or blade ([Fig. 2]).
Fig. 2
(A) Illustration showing that the lamina was grasped at the spinous process and gently
lifted with towel clamp forceps, and the lamina was separated. (B) Intraoperative image showing a complete decompressive laminectomy.
For the conventional group, to remove the lamina, a high-speed burr was used in conjunction
with a Kerrison rongeur to create troughs on either side of laminae and then laminectomy
was completed. In all cases, the pedicle screws were placed via a free-hand technique
with the aid of fluoroscopy, and homeostasis was obtained using gelfoam and bipolar
cautery. All patients who underwent spinal decompression in the present study were
administered tranexamic acid during the operation, and records on intraoperative blood
loss and time from the start of decompression surgery were recorded. Standard closure
was done in layer by layer over a Radivac drain.
Intraoperative blood loss, operating time, laminectomy time, hospital length of stay,
and complications were recorded in both groups.
Statistical Analysis
Statistical analysis was performed with Jamovi 2.3.5 (Sydney, Australia) for Windows.
Chi-squared tests were used to compare categorical data. Continuous data were tested
for normality and compared with either Student t tests or Mann-Whitney U tests depending
on normality. P-values < 0.05 were considered statistically significant. A power analysis
was performed with Epitools (Ausvet, Australia) for the primary outcome measure (mean
bleeding volume).[14] To achieve a minimum power of 0.80 with a confidence level of 0.95, a minimum sample
size of 20 patients was required to detect the minimum important difference in bleeding
volume. To avoid missing or incomplete data, a 30% increase in sample size was added
to the total sample size of 26.
Results
Demographic Data
In the present study, we recruited a total of 31 patients who met the criteria with
a mean age of 57.1 ± 8.0 years old. At the time of surgery, patients in the UBS (15
patients) and conventional (16 patients) groups were similar regarding age, gender,
body mass index, and decompression level ([Table 1]).
Table 1
|
Total (n = 31)
|
UBS (n = 15)
|
Conventional (n = 16)
|
p-value
|
|
Age, years; mean ± SD
|
57.1 ± 8.0
|
51.1 ± 7.8
|
55.5 ± 14.3
|
0.711
|
|
Gender
|
|
|
|
0.376
|
|
Female; n (%)
|
14 (45.2)
|
8 (53.3)
|
6 (37.5)
|
|
|
Male; n (%)
|
17 (54.8)
|
7 (46.7)
|
10 (62.5)
|
|
|
BMI, kg/m2; mean ± SD
|
25.5 ± 4.1
|
26.1 ± 3.7
|
24.9 ± 4.4
|
0.401
|
|
Decompression level; mean ± SD
|
|
|
|
0.945
|
|
Short-segment (≤ 3); n (%)
|
27 (87.1)
|
13 (86.7)
|
14 (87.5)
|
|
|
Long-segment (> 3); n (%)
|
4 (12.9)
|
2 (13.3)
|
2 (12.5)
|
|
Intraoperative Blood Loss
Intraoperative blood loss in the UBS group was found to be lower than in the conventional
group. Intraoperative blood loss in the UBS and conventional group was 656.0 ± 167.6 ml
and 936.9 ± 413.2 ml, respectively ([Table 2]).
Table 2
|
UBS (n = 15)
|
Conventional (n = 16)
|
p-value
|
|
Intra-operative blood loss, ml; mean ± SD
|
656.0 ± 167.6
|
936.9 ± 413.2
|
0.031
|
|
Operative time, mins; mean ± SD
|
215.5 ± 60.7
|
218.4 ± 50.2
|
0.883
|
|
Laminectomy time, mins; mean ± SD
|
54.5 ± 27.4
|
73.4 ± 28.1
|
0.019
|
|
Hospital length of stay, days; mean ± SD
|
8.7 ± 3.2
|
7.7 ± 2.7
|
0.367
|
|
Complications
|
|
|
|
|
Superficial wound infection; n (%)
|
2 (13.3)
|
0 (0)
|
0.131
|
|
Neurological deficit; n (%)
|
0 (0)
|
0 (0)
|
|
|
Dura tears; n (%)
|
0 (0)
|
0 (0)
|
|
Operating Time and Laminectomy Time
The UBS group had significantly less laminectomy time than the conventional group.
The time required for laminectomy in the UBS and conventional groups was 54.5 ± 27.4 minutes
and 73.4 ± 28.1 minutes, respectively. However, the overall operative time was found
to be similar in both groups. The UBS and conventional groups had operative time of
215.5 ± 60.7 mins and 218.4 ± 50.2 minutes, respectively ([Table 2]).
Hospital Length of Stay and Complications
There were no significant differences in hospital length of stay and complications
between the UBS and conventional groups. In the UBS group, 2 of 15 patients (13.3%)
had a superficial wound infection, while there was no superficial wound infection
in the conventional group. There was no evidence of a dura tear or a neurological
deficit in either group. The hospital length of stay of the UBS and conventional groups
was 8.7 ± 3.2 days and 7.7 ± 2.7 days, respectively ([Table 2]).
Discussion
The most important finding of the present randomized controlled trial is that intraoperative
blood loss and laminectomy time are significantly lower in the UBS group (656.0 ± 167.6 ml,
54.5 ± 27.4 minutes) than in the conventional group (936.9 ± 413.2 ml, 73.4 ± 28.1 minutes).
The study demonstrates that overall operation time, hospital length of stay, and complications
are all similar.
Intraoperative blood loss is a common problem, particularly during multilevel spinal
fusion surgeries. Significant blood loss requires frequent blood transfusions throughout
the intraoperative and postoperative periods of multilevel and even single-level spine
surgery.[15] The rates of mortality and morbidity are prominently increased in patients who have
a blood loss > 500 mL during spinal surgery.[16] Several studies also suggest that longer surgical time is a substantial risk factor
for perioperative and postoperative complications, such as deep vein thrombosis, pulmonary
embolism, and surgical site infection.[17] Therefore, reducing intraoperative blood loss and shortening operative time are
of highest concern in spinal surgery. In the present study, the operative time for
UBS and conventional techniques differ significantly, with UBS taking less time. Most
postoperative problems associated with dura tears, such as pseudomeningocele, headache,
postoperative meningitis, and cerebral bleeding, have been reported in previous studies.
According to previous studies, the UBS can selectively cut hard tissues like bone
while sparing soft-tissue structures like the dura mater and nerves, making it at
least as safe and effective in spinal decompression.[18] Both techniques used in our study had no problems related to dura tears. The rate
of intraoperative unintentional durotomy was not different between these 2 techniques,
according to the present study. In addition, as compared to the conventional technique
for thoracolumbar spinal decompression, the UBS did not increase the risk of postoperative
complications while decreasing intraoperative blood loss and minimizing laminectomy
time.
Limitations
The present study has several limitations. First, our study had a sample size of only
31 patients, which means increasing the number of patients could make a difference
in complications. Second, our study did not include clinical outcomes such as neurologic
status and long-term follow-up. Therefore, further studies may increase the JOA score
or Frankel grade. Third, the procedure for inserting pedicular screws and rods under
fluoroscopy using the free-hand technique in each case took a varying amount of time,
which may affect results in intraoperative blood loss, overall operating time, hospital
length of stay, and complications. Finally, the present study has no mid- to long-term
follow-up. Further studies may add the duration of follow-up period to assess possible
complications and long-term clinical outcomes.
Conclusion
Intraoperative blood loss and laminectomy time are significantly lower in the UBS
group than in the conventional group. In conclusion, the UBS is a useful instrument
for procedures performed near the dura mater or other neural tissue without excessive
heat or mechanical injury. This device is recommended for various spinal surgeries
in addition to high-speed burrs and Kerrison rongeurs.
