Values Following Lumbar Decompression Surgery
Tohoku J. Exp. Med., 2013, 229, Hemoglobin
1-4

1Postoperative Anemia Following Posterior Decompression
Surgery for Lumbar Spinal Canal Stenosis
Tatsuro Sasaji,1 Kiyoshi Horaguchi,1 Nobuhisa Shinozaki,1 Noboru Yamada1 andKazuo Iwai1
1Department of Orthopedic Surgery, Fukushima Rosai Hospital, Iwaki, Fukushima, Japan

The incidence of lumbar spinal canal stenosis (LSCS) is increasing in Japan. Posterior lumbar
decompression surgery, wide fenestration and laminectomy, for LSCS is a common treatment modality.
Compared with posterior fusion surgery, posterior decompression surgery has been considered as lessinvasive. However, no reports regarding postoperative anemia following posterior decompression surgery
have been published. In this retrospective study, we evaluated changes in hemoglobin values following
wide fenestration in 80 patients with LSCS based on the number of operated levels, and also analyzed thedifferences between intraoperative and postoperative bleeding volume. Two patients required allogenictransfusion. The mean preoperative hemoglobin values were 13.6 g/dL and the mean postoperative
minimum hemoglobin values were 11.2 g/dL. The mean hemoglobin values decreased by 1.8 g/dL inpatients with one operated level (n = 15); 2.2 g/dL in those with two operated levels (n = 31); 2.6 g/dL in
those with three operated levels (n = 23); and 3 g/dL in those with four operated levels (n = 11). The mean
decrease in hemoglobin values was calculated as follows: 1.8 + 0.4 × (X − 1), where X was the number ofoperated levels. The mean intraoperative bleeding volume was 94 ml and the mean postoperative bleeding
volume was 418 ml. Postoperative bleeding volume was significantly larger than intraoperative bleeding
volume. Accordingly, postoperative hemoglobin values can be predicted in patients undergoing wide
fenestration. Effective management of postoperative bleeding is necessary to prevent postoperativeanemia.
Keywords: anemia; hemoglobin; laminectomy; lumbar; spinal stenosis
Tohoku J. Exp. Med., 2013 Jan, 229 (1), 1-4. © 2013 Tohoku University Medical Press
tive blood salvage in spine surgery was evident. Some
reports have been published regarding the efficacy of intraoperative cell saver blood autotransfusion (Behrman andKeim 1992; Chanda et al. 2002; Gause et al. 2008;
Savvidou et al. 2009); however, no reports have examined
intraoperative and postoperative bleeding volume alongwith changes in hemoglobin values following lumbar surgery. To evaluate the efficiency of autotransfusion, werequire the basic data for bleeding in lumbar decompression
surgery. In this study, differences between the intraoperative bleeding volume and total postoperative bleeding volume, as well as changes in hemoglobin values based on thenumber of operated levels were analyzed in patients who
had underwent posterior lumbar decompression surgery.

Lumbar spinal canal stenosis is prevalent in elderly
people. Japan is an aging society, with increasing incidenceof this disorder. Consequently, most patients that require
lumbar surgery are elderly; therefore, general control ofpostoperative condition in this population is important. The
main postoperative control points for lumbar surgery areusually infection and bleeding. Fusion surgery is moreinvasive than decompression surgery. And so, papers
regarding postoperative control of fusion surgery have beenpublished. Some detailed reports have been publishedregarding the inflammatory reactions that occur after spinal
instrumentation surgery (Takahashi et al. 2001, 2006).
Other reports have addressed the issues of bleeding volume
and anemia following posterior fusion surgery (Behrmanand Keim 1992; Gause et al. 2008). According to Behrman
and Keim (1992), major orthopedic procedures such as
spine surgery often entail significant blood loss. Gause etal. (2008) reported that elective posterior spinal surgery
necessitates the use of blood for the treatment of postoperative anemia. In both reports, the importance of periopera-Materials and Methods
We retrospectively reviewed the medical records of 80 consecutive cases (37 females and 43 males, aged 55-88 years, mean age 71years) referred to our institute for surgical treatment between 2010
and 2011 and underwent follow-up examinations for a minimum ofReceived September 25, 2012; accepted November 8, 2012. Published online November 27, 2012; doi: 10.1620/tjem.229.1.
Correspondence: Tatsuro Sasaji, Department of Orthopedic Surgery, Fukushima Rosai Hospital, 3-Numajiri, Tsuzura-machi, Uchigo,Iwaki, Fukushima 973-8403, Japan.
e-mail: taturosasaji@hotmail.com

12T. Sasaji et al.
the Student’s t-test. A probability value of less than 0.05 was considered significant. Statistical analyses were performed using GraphPad
Prism (GraphPad Software Inc., San Diego, CA, USA). All thepatients were informed that the data from their cases would be used
for this study. The protocol for this study was approved by the Ethics
Committee at Fukushima Rosai Hospital (Iwaki, Japan).

ResultsFig. 1. Surgical schemata displaying wide fenestration (onelevel).
The shaded area was decompressed. The bilateral medialparts of the inferior facets and the bilateral cranial partsof the lamina and the adjoining ligamentum flavum wereremoved. The wide fenestration decompressed the dura
and nerve roots in the entry zone.

one-year. The mean follow-up period was 16 months (range, 12-28months). The diagnosis of lumbar spinal canal stenosis (LSCS) wasbased on clinical symptoms, neurological examinations, and results ofmagnetic resonance imaging. All the patients had typical neurological symptoms of cauda equina syndrome including bilateral radiating
leg pain, numbness, and intermittent claudication. Exclusion criteria
for this study included fusion surgery, prior lumbar spinal surgery,foraminal stenosis and intraoperative dural tear. For cases receiving
anticoagulant and antiplatelet drug therapy, treatment discontinued
and substituted by heparin therapy for several days before surgery.
The absolute indication for allogenic transfusion was hemoglobinvalues of below 8 g/dL.
All surgeries were performed by a single spinal surgeon. Widefenestration was performed in all patients (Nakai et al. 1991; Fig. 1);
thereafter, continuous suction drains were used after surgery.
Intraoperative bleeding volume along with postoperative bleeding volume on postoperative day 1, and total postoperative bleeding
volume were measured; here, the drainage volume was defined as
postoperative bleeding volume. Hemoglobin values were measured
the day before surgery and on postoperative days 1, 2, 3, 5, and 7.
Differences between intraoperative bleeding volume and total postoperative bleeding volume were analyzed. The percentage of postoperative acute-phase bleeding was calculated as follows: (bleeding volume on postoperative day 1)/(total postoperative bleeding volume) ×100. A decrease in hemoglobin values was defined as follows: (preoperative hemoglobin values) − (minimum postoperative hemoglobinvalues). All cases were divided into groups based on the number ofoperated levels; subsequently, the decrease in hemoglobin values wasevaluated.
For statistical purposes, data for bleeding were compared using

Two of the patients required allogenic transfusion for
postoperative anemia. The minimum postoperative hemoglobin values were 7.4 and 7.9 in these cases. The mean
intraoperative bleeding volume ± standard deviation was 94± 42 ml (range, 14-569 ml), and the mean total postoperative bleeding volume was 418 ± 189 ml (range, 100-1185ml; Fig. 2). The mean total postoperative bleeding volume
was significantly larger than the mean intraoperative bleeding volume (P < 0.001). The mean bleeding volume on
postoperative day 1 was 249 ± 105 ml (range, 40-560 ml).
The mean percentage of postoperative acute-phase bleedingwas 61 ± 12 % (range, 34-94 %). The mean preoperative
hemoglobin values were 13.6 ± 1.6 g/dL (range, 8.5-17.6 g/dL) and the mean postoperative minimum hemoglobin values were 11.2 ± 1.5 g/dL (range, 7.4-15.5 g/dL). One level
was operated in 15 patients, two in 31 patients, three in 23patients, and four in 11 patients. Hemoglobin values
decreased by 1.8 ± 0.6 g/dL (range, 1-3.2 g/dL) in patientswith one operated level, 2.2 ± 0.6 g/dL (range, 1.1-3.7 g/dL) in those with two operated levels, 2.6 ± 0.8 g/dL (range,1.2-4 g/dL) in those with three operated levels, and 3 ± 0.8g/dL (range, 1.6-4.6 g/dL) in those with four operated levels. The mean decrease in hemoglobin values was calculated as follows: 1.8 + 0.4 × (X − 1), where X was the number of operated levels (Fig. 3).

Discussion
Posterior lumbar surgery for LSCS is a common treatment modality in Japan. The types of surgery vary and thelevels to be operated differ for each case. For invasive surgeries such as fusion surgery and scoliosis surgery, themanagement to prevent allogenic transfusion has been
examined (Behrman and Keim 1992; Chanda et al. 2002;
Brookfield et al. 2008; Gause et al. 2008; Savvidou et al.
2009). However, for less invasive surgery such as decompression surgery, postoperative anemia has not been evaluated in detail. In this study, perioperative anemia, perioperative bleeding volume, and changes in hemoglobin values
were evaluated.
The postoperative decrease in hemoglobin values
according to the number of operated levels has not been
evaluated. In this study, the mean decrease in hemoglobinvalues according to the number of operated levels was constant. The formula presented above facilitates the prediction of postoperative hemoglobin values in patients whounderwent posterior lumbar decompression surgery. The
results indicate that management of postoperative anemia isessential if the predicted postoperative hemoglobin values

Hemoglobin Values Following Lumbar Decompression Surgery

Fig. 2. Comparison of intraoperative and total postoperative bleeding volume.
The mean intraoperative bleeding volume ± standard deviation was 94 ± 42 ml (range, 14-569 ml), and the mean total
postoperative bleeding volume was 418 ± 189 ml (range, 100-1,185 ml). The total postoperative bleeding volume wassignificantly larger than the intraoperative bleeding volume (P < 0.001). The error bars represented the standard deviation of the measured bleeding volume.

Fig. 3. Changes in hemoglobin values according to the number of operated levels.
The mean decrease in hemoglobin values was 1.8 ± 0.6 g/dL in patients with one operated level, 2.2 ± 0.6 g/dL in thosewith two operated levels, 2.6 ± 0.8 g/dL in those with three operated levels, and 3 ± 0.8 g/dL in those with four operatedlevels. The mean decrease in hemoglobin values increased by 0.4 g/dL per one level increased. The mean decrease inhemoglobin values was calculated as follows: 1.8 + 0.4 × (X − 1), where X was the number of operated levels. Theerror bars represent the standard deviation of the measured hemoglobin values.

34T. Sasaji et al.

were below 8 g/dL.
Previous reports have discussed the efficacy of intraoperative cell saver blood autotransfusion to prevent allogenic transfusion (Behrman and Keim 1992; Chanda et al.
2002; Brookfield et al. 2008; Gause et al. 2008; Savvidou etal. 2009). However, these reports did not compare intraoperative and postoperative bleeding volume. In this study,
postoperative bleeding volume was significantly larger thanintraoperative bleeding volume. In addition, the bleeding
volume on postoperative day 1 accounted for more thanhalf of the total postoperative bleeding volume. To prevent
postoperative anemia, management of postoperative hemorrhage is important, especially that occurring on the day ofsurgery.
No reports on the postoperative anemia following
lumbar decompression surgery for LSCS are available. On
the basis of present study, we assume that the predicting
formula is useful for selecting the appropriate management
to prevent postoperative anemia. But, the number ofpatients was small in the present study. And so, furtherstudies with a large number of LSCS patients would be necessary.

Conclusion
In cases of posterior lumbar decompression surgery,decrease in hemoglobin values can be predicted before surgery. To prevent postoperative anemia and the need forallogenic transfusion, management of postoperative bleeding is of vital importance.

Conflict of Interest
The authors declare no conflict of interest.

References
Behrman, M.J. & Keim, H.A. (1992) Perioperative red blood cellsalvage in spine surgery. A prospective analysis. Clin.
Orthop. Relat. Res., 278, 51-57.
Brookfield, K.F., Brown, M.D., Henriques, S.M., Buttacavoli, F.A.
& Seitz, A.P. (2008) Allogeneic transfusion after predonationof blood for elective spine surgery. Clin. Orthop. Relat. Res.,
466, 1949-1953.
Chanda, A., Smith, D.R. & Nanda, A. (2002) Autotransfusion bycell saver technique in surgery of lumbar and thoracic spinal
fusion with instrumentation. J. Neurosurg., 96, 298-303.
Gause, P.R., Siska, P.A., Westrick, E.R., Zavatsky, J., Irrgang, J.J.
& Kang, J.D. (2008) Efficacy of intraoperative cell saver indecreasing postoperative blood transfusions in instrumented
posterior lumbar fusion patients. Spine, 33, 571-575.
Nakai, O., Ookawa, A. & Yamaura, I. (1991) Long-term roentgenographic and functional changes in patients who were treatedwith wide fenestration for central lumbar stenosis. J. Bone
Joint Surg. Am., 73, 1184-1191.
Savvidou, C., Chatziioannou, S.N., Pilichou, A. & Pneumaticos,S.G. (2009) Efficacy and cost-effectiveness of cell saving
blood autotransfusion in adult lumbar fusion. Transfus. Med.,19, 202-206.
Takahashi, J., Ebara, S., Kamimura, M., Kinoshita, T., Itoh, H.,
Yuzawa, Y., Sheena, Y. & Takaoka, K. (2001) Early-phaseenhanced inflammatory reaction after spinal instrumentation
surgery. Spine, 26, 1698-1704.
Takahashi, J., Shono, Y., Hirabayashi, H., Kamimura, M.,
Nakagawa, H., Ebara, S. & Kato, H. (2006) Usefulness ofwhite blood cell differential for early diagnosis of surgicalwound infection following spinal instrumentation surgery.
Spine, 31, 1020-1025.